Newsletter – 14th
March 2022
Revealed: the truth about the 1931 Census EXCLUSIVE
How the census changed from 1841 to 1921
Last chance to save on old newspapers ENDS TODAY
Ancestry DNA offers ENDING SOON
Masterclass: How to make the most of your DNA
test UPDATED
The LostCousins
newsletter is usually published 2 or 3 times a month. To access the previous issue
(dated 11th March) click here; to find earlier articles use the customised Google search between
this paragraph and the next (it searches ALL of the newsletters since February
2009, so you don't need to keep copies):
To go to the main
LostCousins website click the logo at the top of this newsletter. If you're not
already a member, do join - it's FREE, and you'll get an email to alert you
whenever there's a new edition of this newsletter available!
Revealed: the truth about the 1931 Census EXCLUSIVE
For
years I've been trying to ascertain the truth about how the 1931 England &
Wales Census came to be destroyed; some of you may remember me broaching the
topic in my 2010 article
What DID happen to the 1931 Census?
All
family historians know that around 60% of army service files from the Great War
were destroyed by enemy action during World War 2, and many know that the
bombing of the Exeter Probate Registry led to the loss of many Devon wills and
probate records. It's inevitable that when we heard that the 1931 Census was
destroyed during WW2 we'd assume that Adolf Hitler was
somehow responsible.
But
as I pointed out in 2010:
"The census schedules, enumeration books,
and other documents relating to the 1931 Census were kept in an Office of Works
furniture store in Hayes, Middlesex. On the evening of Saturday
19th December 1942 the store was gutted by fire, the cause of which was
never identified."
Many
sources refer to the accidental destruction of the records, but I was sceptical:
"Since
there were special fire hydrants in the store, and there was a guard of 6 fire
watchers, it seems incredible that the fire could have developed to such
disastrous proportions. I don't know whether there was an enquiry at the time,
but I wonder whether it may have been significant that it was not only a
Saturday night, but also the last Saturday before Christmas? Was there some sort of Christmas
celebration going on behind the blackout curtains?"
Until
now I've been unable to find any contemporary commentary on the cause of this
disaster, but on Friday I discovered a letter in the National Archives which
confirmed my suspicions:
©
Crown Copyright
So there we have it: "criminal negligence or
sabotage". Clearly the loss of the 1931 Census for England & Wales was
not the unfortunate accident that we've been led to believe.
Note:
this letter, addressed to Mr V P A Derrick of the General Register Office, can
be found in RG 20/109. These papers can currently be downloaded free of charge from
the National Archives when you follow this link.
It's
not just the 1931 Census that was lost – the Enumeration Books for the 1921
Census were also stored at Hayes and perished in the fire. Who were the 6 fire
guards whose apparent 'criminal negligence' led to the
destruction? That's my next challenge….
How the census changed from 1841 to 1921
When
I began researching my family tree I purchased Making
Sense of the Census by Edward Higgs. Published by the Public Record Office
(as it then was) in 1989, it provided a handy guide to the information
collected – and not collected – in the censuses from 1801-1901. (The 2005
revised edition is still available from Amazon)
But
much of the key information is available free in a research guide on the National
Archives website – you'll find it here.
You
might think that after all this time you know all there is to know about the
census returns, but I certainly learned some thing new, and I suspect you will
too!
Last chance to save on old newspapers ENDS TODAY
Until
midnight (London time) today, Monday 14th March, you can save a massive 30% on
subscriptions to the British Newspaper Archive. For example, a 12 month subscription comes down to just £56, little more
than £1 a week.
If
you have a Pro or Ultimate subscription to Findmypast you'll already have
access to the nearly 50 million pages in the archive, but newspapers aren't
included in lesser subscriptions. And even if you do have a Pro subscription,
heavy users of historic newspapers will appreciate the more flexible searching
options – for example you can restrict your searches to pages added to the
archive after a certain date, so that you don't keep ploughing through the same
list of results and can focus on what's new - this is important because the
archive is growing by upwards of 4 million pages a year.
This
offer isn’t exclusive to LostCousins, but I'd appreciate it if you could click
the link below when you make your purchase, as you'll be helping to support the
LostCousins project to connect family historians around the world who are
researching the same ancestors.
British
Newspaper Archive – SAVE 30% UNTIL MIDNIGHT (London time) MONDAY 14TH
Ancestry DNA offers ENDING SOON
The
news about Ancestry's latest offers didn’t arrive in my inbox until after the
last newsletter was published, so whilst I did add them to the Stop Press
for that issue, I suspect many readers won't have noticed.
The
St Patrick's Day offers in the US and Australia end just before midnight on Thursday
17th March, so you'll need to be quick; you've got longer to take advantage of the
Mother's Day offer in the UK. Please use the relevant link below so that you
can support LostCousins when you make your purchase (you may find that you need
to log-out from Ancestry, then click the link again):
Ancestry.com.au
(Australia & New Zealand only) – $89 plus shipping until 17th March – SAVE $40
Ancestry.com
(US only) – $59 plus shipping until 17th March – SAVE $40
Ancestry.co.uk
(UK only) – £59 plus shipping – SAVE £20
Of
course, Ancestry DNA isn't just for mothers and those with Irish ancestry –
anyone can take the test. You don’t need to decide who is going to test when
you place your order – only when the test is registered.
Note:
to meet privacy requirements all those who test with Ancestry must have an
account in their own name, but they can hand over the management of the test to
a relative, usually someone who has an Ancestry subscription.
If
you don't understand DNA then you're not in the minority – the reality is that very
few people truly understand how it works and the implications for family
historians.
In
many ways using DNA is like driving a modern car – you don't need to know
what's under the bonnet, you just need to know what it can do, and how to
control it. Indeed, you'll probably find it comforting to know that the less
you know about the nuts and bolts of DNA the more successful you're likely to
be!
I've
been using DNA for the past 10 years, and during the first half of that decade
I was devouring DNA blogs, articles, and books in an attempt
to achieve more from a small number of matches. It was frustrating,
challenging, and ultimately fruitless – I didn't knock down a single 'brick
wall'.
Five
years ago I re-tested, this time with Ancestry, and within
weeks I was getting the results I'd been looking for all along!
Not
only were some of my oldest 'brick walls' tumbling down, I
was able to validate much of my paper-based research by making use of the
matches I had with distant cousins. This was very reassuring because a lot of
research had been done the hard way, poring over microfiche and microfilm, and
when you're working under those conditions it's very tempting to accept the
first plausible baptism or marriage that you find.
To
make the best use of my Ancestry matches I had to forget most of what I'd learned
during those five frustrating years, and instead focus on making the most of
the opportunities that Ancestry provided. It breaks my heart to hear from
members who have been reading up on DNA techniques and tools, because I know that
it's only going to make it more difficult for them.
When
it comes to DNA a little knowledge is a good thing – it only gets dangerous when
you step beyond the bounds of my Masterclass….
Masterclass: How to make the most of your DNA test
Note: I've updated this Masterclass since
it was last published in March 2021
We
all have 'brick walls' in our trees - in some cases because our ancestors were
illegitimate, in others because of deficiencies in the records. Fortunately, because
our DNA is inherited from our ancestors it's also a record of our ancestry – one
that can not only overcome gaps in the archives but also provide us with a way
of checking that our research is correct.
Tip:
DNA doesn't replace conventional research, it provides
a second layer of connections. It's a bit like overlaying a map onto a satellite
image – they are different ways of looking at the same thing, and in most cases each will corroborate the other.
You
probably don’t have samples of your ancestors' DNA to compare yours against - though
it's technically possible to extract DNA from hair or the gum on the back of a
used postage stamp, it's not a service that mainstream companies offer. But there
are lots of other people who do have samples for comparison – your cousins. They
inherited their DNA from their ancestors, and whilst most of their ancestors will
be different from yours, any segments of DNA that you share were almost
certainly inherited from your common ancestor(s).
Note:
anyone who shares some of your ancestors is a cousin of yours, no matter how
distant the relationship; in fact, distant cousins are particularly useful when
it comes to knocking down 'brick walls', though close cousins can also play a
part.
We
can’t all be DNA experts – and the good news is that provided you follow the
advice in this Masterclass, you'll be able to get amazing results even if you don’t
understand the first thing about the science behind DNA. Indeed
there are plenty of people who do know quite a lot about DNA who would probably
achieve more if only they stuck to the simple strategies in this Masterclass!
Here's
all you really need to know:
· Most of the DNA tests
on offer to family historians, and the only ones you should be seriously considering,
are autosomal DNA tests; they can taken
by both males and females, and they have the potential to solve puzzles
anywhere in your family tree within the last 6 or 7 generations (around 250 years),
but can sometimes reach back even further.
· All
of
your DNA comes from your ancestors, but you inherit only half of your parents' autosomal
DNA, they only inherited half of their parents' DNA, and so on. So always test
the earliest generations.
· Unlike personal traits
and some hereditary diseases, DNA doesn’t skip a generation - you can't possibly
inherit a segment of DNA from a grandparent unless your parent inherited it
first
· Just because you and
your cousins share ancestors this doesn't necessarily mean that you'll share
DNA - you could have inherited different bits of DNA from the ancestors you
share; the closer the cousin, the more DNA you're likely to share, but despite this distant cousins are often more useful (partly because there
are so many more of them!)
Which test should you
choose?
Don’t
make your decision based on price; although all of the
main DNA tests on offer are technically similar, what you're looking for is to
get as many matches with genetic cousins as possible. Ancestry have by far the biggest database, with around 20 million
users, and the only way to get access to that database is to buy the Ancestry
test.
Note:
you might think that 20 million is a small number compared to the population of
the world, and it is – but it's large number compared
to the number of people in the world who subscribe to Ancestry, which is closer
to 3 million.
Most
other test providers allow transfers – but Ancestry don't, and that's why it’s crucial
to test with them. You can always upload your data to other sites later, but
you can't go the other way. Another reason to choose the Ancestry test is the
way they integrate DNA with family trees – it works really, really
well (as you would expect from a company that has been in the genealogy
business far longer than any of their competitors).
The
reason I tested my DNA, and persuaded some of my cousins to join in, was to
knock down 'brick walls' that conventional research couldn't breach. The sad reality
is that if our 'brick walls' have resisted our efforts for years (or even
decades), it’s unlikely that they're ever going to come crashing down if all we
have to go on are the records that have survived down
the centuries.
DNA
can help by bridging gaps in the records and compensating for errors, but it means
adopting new and unfamiliar strategies, and utilising somewhat different
techniques to the ones that we're used to. But if you follow the steps in this
Masterclass you won’t have to go through the steep learning curve that I did,
nor will you make the mistakes that I did in the early days,
before Ancestry started selling their test in the UK.
Before
you even get your results.....
DNA
isn't a substitute for researching the records – you need both. So make sure that you do all the conventional,
records-based, research you reasonably can while you’re waiting for your
DNA results, so that when they come through you're ready to go. Don’t leave it
until the last moment, because in my experience the results invariably arrive
well ahead of schedule, typically 4 weeks or less rather than the 6-8 weeks
that Ancestry quote.
There
are two types of cousins
Genetic
cousins
are the cousins you find by testing your DNA – but usually you won't know exactly
how you're related to them, indeed you might not have a
clue what the connection is! And that's where documented cousins come in
– they're the cousins you can fit onto your family tree because you know precisely
how they're related to you.
The
most valuable cousins are both genetic and documented, and there are several
ways to come up with them:
You
can't do the first two until you get your DNA results through, and it might be
hard to persuade your cousins to test if you're still waiting for your own
results, even if you offer to pay. But the fourth option is open to you right
now, because there is a great source of documented cousins who have already
tested – amongst the LostCousins membership!
Connect
with documented cousins
Complete
your My Ancestors page at the LostCousins
site, ensuring that you have entered ALL of the
cousins that you can find on the 1881 Census. Because your living cousins are
descended from the branches of your tree it's the relatives from the branches
who are most likely to connect you to them. For example:
3rd,
4th, and 5th cousins are ideal when you’re working with DNA. If you’re younger
than me and your grandparents weren't born until after 1881 you could look at
it this way:
Completing
your My Ancestors page might take you an hour or two, but it's easy to
do and could save you money – if you don't find some 'lost cousins' who have
already tested you're likely to end up paying for known cousins to test.
But
it’s not just about money – connecting with documented cousins who have already
tested could save you hundreds of hours you might otherwise spend fruitlessly analysing
your DNA matches. DNA is like a jigsaw puzzle – the more pieces you can fit in
place the easier it is to figure out how everything else fits in. DNA matches
with documented cousins are the edge pieces of the jigsaw.
Tip: start with all
the relatives you can identify in 1841, whether or not
you can actually find them on that census, then trace each of your branches (sometimes
referred to as collateral lines) through to 1881. Remember that ALL of your living cousins are descended from the branches
of your tree, so every branch and every twig is a potential link to a 'lost
cousin'.
On
my own My Cousins page there are 17 cousins who have tested (indicated
by 'Y' in the DNA column), and 2 who are considering it (shown by an 'M'). If
there is no entry in the column it's worth checking with your cousin in case they forgot to update their My Details page when
they tested.
Tip:
DNA status is only shown for cousins who you have connected with – it isn't
shown for New Contacts, or relatives who have not been identified as cousins
(and may only be related by marriage).
How
your cousins can best help
Shared
matches are the key – if you and a documented cousin match the same genetic
cousin then it’s overwhelmingly likely that the genetic cousin is descended
from one of the ancestral lines that you and your documented cousin share. When
you view a DNA match with any cousin at Ancestry you can click Shared
Matches to find out which other cousins you both match.
Note:
Ancestry only show shared matches where both matches exceed 20cM.
If
your cousins also tested with Ancestry ask if they would be prepared to make
you a Viewer of their DNA results – this enables you to see ALL of their matches, whether they share them with you or
not, and allows you to check for shared matches where the 20cM threshold has
not been reached.
Note:
as a Viewer or Collaborator you can see another user's matches and their
ethnicity results, but you don’t have access to their raw DNA results.
Being
able to see ALL of a documented cousin's matches
enables you to benefit from the matches they've made with genetic cousins who
share your ancestors but who don’t appear in your own list. Remember what I
said earlier: just because you and a cousin share ancestors doesn’t mean that
you'll share DNA. For example, the chance of two 5th cousins sharing detectable
DNA is about 1 in 3, so most of your 5th cousins who have tested won't appear
in your list of matches – but they might appear in your cousins' lists, so the
more documented cousins you collaborate with, the greater your chances of knocking
down your 'brick walls'.
Everything
I've written about so far can be done before you get your DNA results,
so that you can be ready to "hit the ground running" when they
arrive. But if you've already had your DNA results it's not too late to go back
and fill in the gaps – indeed, it would be foolish not to.
How to
process your DNA matches
I'm
going to assume for the purpose of this article that you tested with Ancestry –
but don't stop reading if you tested elsewhere because some of the strategies can
be used at other sites.
At
Ancestry you'll typically have over 10000 matches with genetic cousins, and of
those about 97% will be with 'distant' cousins, ie where the estimated relationship is 5th cousin or
more distant. So you might think that the best
strategy might be to focus on the top 3%, on the basis that if you can't make
head or tail of those matches, your chance of resolving the more distant
matches is negligible.
But
you couldn't be more wrong – your 'brick walls' are most likely to be solved by
matches that Ancestry regards as distant matches, and this is partly because
nobody, not even Ancestry, can accurately determine precisely how close a DNA match
is once you get beyond 1st cousins. For example, one of my 3rd cousins and
closest collaborators is shown by Ancestry as a 5th to 8th cousin because the amount
of DNA we share is lower than average (but still within the normal range for
3rd cousins).
This
means that simply working your way through the list from the top isn’t a great
strategy. It inevitably will lead to wasted time and frustration, not least
because many of your cousins won't have trees, and many of them won't reply to
your messages.
Fortunately 5 years of using Ancestry DNA (and another 5
years before that trying to use DNA at other sites) have taught me a few things.
Here's how to get the best results and avoid all the wasted time and
frustration…..
Upload
a tree and connect it to your DNA results (no subscription needed)
I
have a public tree connected to my DNA results, but it only includes my direct
ancestors – this makes it useful for my cousins, but of little interest to name
collectors and the like. It also protects the privacy of my living cousins, since their branches aren't included. You don’t need
to have a public tree, but you do need to have a tree connected to your DNA to
make use of the advanced features which I'm going to tell you about next.
Common
Ancestors (no subscription needed)
The
Common Ancestors feature, which utilises online trees to figure out how
you and some of your matches are connected. It's something you could do
yourself if you had an Ancestry subscription, unlimited time, and a brain like
a computer, but having Ancestry do it for you will provide a real boost.
About
1.4% of my DNA matches are flagged as having common ancestors: but what really stands
out is that more than half of them are distant matches, and some of them have
very small trees, some with under 10 relatives.
You
might be wondering how Ancestry can identify one of my distant matches as
having Common ancestors when she has only 4 people in her tree – it’s because
they're looking at ALL the tens of millions of online trees in their database,
not just the ones that belong to my DNA matches. That's why you'd need
unlimited time and a brain the size of a planet to do it yourself!
In
this case clicking reveals
that the common ancestors are our great-great grandparents William Pepperell
and Mary Ann Burns – making her my 3rd cousin, though once again the amount of
shared DNA is below average for a 3rd cousin, which is why she's shown as 4th
to 6th cousin.
When
the common ancestor(s) are shown click the name of the ancestor to see how the
two of you are descended from that person (the information in the first column
will be based on the tree you've connected to your DNA results).
Always
bear in mind that online trees often include errors – just because you have a
DNA match with someone doesn't mean that their tree is correct, although it
certainly improves the odds! However the information for
each generation will usually be supported by multiple trees uploaded by
different users, which is another encouraging factor.
When
I've verified the connection I add a brief note against the DNA match at
Ancestry, then add the cousin to the tree on my own computer, which often entails
adding a new branch. At this point it may be apparent that there are relatives
I can add to the My Ancestors page at the LostCousins site (to find
further cousins), and doing it there and then makes it
sure that it isn’t forgotten.
ThruLines™ (no subscription needed)
Ancestry's
ThruLines™ feature uses Ancestry trees in an attempt to knock down 'brick walls'. It was introduced
before Common Ancestors, which it overlaps to an extent, but it's still
worth checking out.
When
you access ThruLines™ it displays the
direct ancestors on your tree, generation by generation, and as you move the
mouse over each box it indicates matches with genetic cousins who share that
ancestor. Even if you don’t have an Ancestry subscription you can see how you’re
connected to those cousins, and as with Common Ancestors the algorithm
utilises all Ancestry trees, public and private searchable, not just those that
belong ot your DNA matches.
However,
if you don’t have an Ancestry subscription you can't view the trees of people
who aren't DNA matches, and even for those who are matches, you can only see 4
generations of their direct ancestors (ie
back to their great-great grandparents). Nevertheless, ThruLines™
is a useful feature that will provide many clues.
Tip:
you don’t need an Ancestry subscription to view a tree if you have been invited
by the tree owner, but without a subscription you can only contact other
members who are DNA matches of yours.
Where
ThruLines™ really pays off is when it knocks
down 'brick walls', by suggesting possible ancestors who don't appear on your
tree. These are usually highlighted in green (rather than pink or blue) - the
screenshot below shows an example:
Tip:
any clues you get from ThruLines™ should be carefully
checked, just as you would any other hints – don't assume that just because the
other person is a DNA match their tree must be correct.
Even
if ThruLines™ doesn't break down any of
your 'brick walls' immediately, bear in mind that it will be updated as other
users test, and as those who have already tested add to their trees.
As
you've worked your way through your Common Ancestors matches, and your ThruLines™ you'll have been able to make
notes against many of your matches to indicate how you're connected to them. But
still the vast majority of your matches, even your
close matches, will have nothing against them. The next step is to fill in some
of the gaps by making use of Shared Matches.
Shared
Matches (no subscription necessary)
There
are two distinct ways to use Ancestry's Shared Matches feature, and they
won't necessarily produce the same results – this is because Ancestry only shows
shared matches of 20cM or more.
The
first way is to work through your close matches (the ones who share 20cM or
more with you); this will reveal which of your other close matches they also
share, even if they don’t have trees of their own, or have minimal trees. Don’t
jump to unjustified conclusions – for example, just because cousin A is a
shared match with cousin B, who shares your Smith and Jones lines, doesn't mean
that cousin A also shares those lines, because the connection could be further
back.
The
second way to make use of Shared Matches is to start with the cousins
whose connection you already know, thanks to Common Ancestors and ThruLines™. Many of them will be distant
cousins of yours, ie they
share less than 20cM with you, but that doesn’t stop them sharing more than
20cM with some of your close cousins. For example, I have 8 shared matches with
the 3rd cousin I referred to previously, even though Ancestry tell me that we only share 10cM of DNA.
The
latter approach has the potential to pick up more shared matches, so it’s well worth
doing.
Groups
(no subscription needed)
Ancestry
allow you to allocate matches to one of 24 groups,
each identified by a coloured circle of a different colour. Precisely how you
use the groups is up to you, but note that you can display
all the matches in a group and search within that group.
I
use blues and greens for my father's side of the tree and reds and yellows for
my mother's side, but how you make use of the groups is entirely up to you. A
match can be in more than one group so if, for example, you allocated a colour
to each of your 16 pairs of great-great-great grandparents there would be just
one dot against your 4th cousins, two against each of your 3rd cousins, and so
on.
Even
if you don't know precisely how you are related to one of your matches you
might be able to allocate them to a group based on shared matches. This is a
very useful technique for adoptees or others who have an unknown parent – typically
the matches to focus on will be the ones that aren't in any groups.
Note:
you can also 'star' matches – it’s like an extra group. I use this feature to
highlight matches which are worth taking another look at.
What
to do next…..
Making
use of the simple tools that Ancestry provides is a great way to make some headway,
but you're really only scratching the surface - it's
likely that your connection to over 95% of your DNA matches is still a complete
mystery.
What
you need now are some simple, straightforward strategies that will lead you to
the matches most likely to help you knock down your 'brick walls':
Strategy
1: search by surname (no subscription needed)
Ancestry
allow you to search the trees of your matches by surname,
so that you can identify cousins who have the same ancestral surname in their
tree as one of your ancestors.
There
are two factors that make this a particularly useful strategy: one is that the
search only looks at ancestral surnames, so ignores names that only appear in
branches of your match's tree; the other is that the search looks at private
trees as well as public trees (provided those private trees are designated as
searchable, which almost all are).
Here's
how to go about it:
Strategy
2: search by birthplace (no subscription needed)
As
you will have discovered when working through your list of surnames, most of
the time the surname of the ancestors you share with a DNA cousin doesn't
appear in both trees - indeed, it's quite possible that the surname of your
common ancestor doesn't appear in either tree!
The
problem is, when your female ancestors married they generally
took their husband's surname. This makes it more difficult to research female
ancestors whose children were born before the commencement of civil registration,
since baptism registers don't usually give the mother's maiden surname -
usually the only solution is to find the marriage. By contrast you can continue
researching your male ancestors even if you can't find their marriage.
Of
course, this problem doesn't simply affect you and your research - it affects
your cousins too; most researchers' trees become increasingly sparse with each
generation. If you've only identified 10% of your 256 6G grandparents and your
cousins have only identified 10% of theirs, the odds of finding out how you're
related to a 7th cousin simply by comparing the names in your trees are pretty remote (a little more than 1% in this example, not
great odds).
Another
way to figure out the connections to your DNA cousins is to look for
geographical overlaps - and here's how to go about it:
Strategy
3: look for overlaps with the more unusual components of your ethnicity (no
subscription needed)
Most
readers of this newsletter have mostly British, Irish, or western European
ancestry. But some of you will have Jewish ancestors, or ancestors from outside
Europe, and whilst ethnicity estimates can be quite misleading, they do provide
another way of analysing your matches.
Here's
what Ancestry show for one of my DNA cousins:
If
Ancestry had detected a Jewish component of my own ethnicity this would be one of
the matches I'd be looking at very closely.
Strategy
4: look for the 'elephant in the room'
Because
we all have 'brick walls' in our trees there are parts of our ancestry that are
a closed book - yet there will inevitably be clues amongst our matches, if only
we look for them. For example, if - like me - you don't know of any Irish ancestors,
but have lots of matches with cousins who do, you might begin to wonder whether
one of your 'brick walls' is concealing a connection to Ireland. I can't
provide you with a step-by-step guide - it's all about awareness (Louis Pasteur
said that "chance favours the prepared mind").
But
beware of the common situation in which you share a single DNA segment with
lots of people who all match each other. This suggests that the people you’re
matched with come from an endogamous population, one in which people generally
marry within the same community - in this case you would probably do well to
ignore the matches altogether as any connection is likely to be a long way back.
More
tips
.
Technical
information
Most
of the matches we make with DNA cousins will be many generations back, since we
have many more distant cousins than we do close cousins. The final column of
the table below indicates roughly how many cousins you might expect to find if
you and they all took the Ancestry DNA test:
Based
on Table 2 from: Henn BM, Hon L, Macpherson JM, Eriksson N, Saxonov
S, Pe'er I, et al. (2012) Cryptic Distant Relatives Are Common in Both Isolated and Cosmopolitan
Genetic Samples. PLoS ONE 7(4): e34267. doi:10.1371/journal.pone.0034267
Revised
using Ancestry DNA estimates for the chances of detecting cousins and the
expected number of 1st to 6th cousins for those of British
ancestry; the numbers for 7th to 10th cousins are my own guesstimates
Of
course, in practice only a small fraction of your cousins will have tested - even
Ancestry, by far the biggest providers of autosomal tests, have sold fewer than
20 million tests - but you can nevertheless reckon that the cousins you're matched
with will be distributed roughly in proportion to the figures shown above. In
other words, over 98% of your matches will be with relatives who are at best
5th cousins, and could well be 8th cousins or even more
distant. This won't necessarily be apparent when you look at your list of
matches because there's a tendency for matches to appear closer or more distant
than they really are.
Tip: Ancestry won't
show any of your DNA matches as more distant than '5th to 8th cousin', but it's
very likely that amongst them there are many who are more distant. Once you get
beyond 3rd cousins the length of the shared segment(s) is only a very rough
guide to how closely you are related - you could share a 20cM segment with a 10th
cousin, but no detectable DNA with a 3rd cousin. The same limitations apply at
other sites too, of course.
This
amazing chart from Blaine Bettinger's blog shows how variable the
amounts can be, and how this affects the amount of DNA shared by more distant
relatives (there is a more recent version of the chart, but I find this one works better):
In
each box there are three figures: the lowest and highest amounts shared between
relatives of each order, together with the average. However
the average only takes into account matches - if there was no detectable shared
DNA it isn’t taken into account in the averages (but does show in the range).
What
you will notice is that the average stabilises at around 12 or 13cM even for
the most distant relationships in the chart. For example, you can see from the first
table that the average DNA shared between 8th cousins is just 0.055cM, but the
average in this chart is over 200 times greater. How can this happen? It's
because unless there's a matching segment of at least 6 to 10cM most companies
won't report a match at all - and because the chart only includes matches which
were actually detected, it bumps up the average quite
considerably.
Very
interesting, you might think - but what does it actually mean
in practice? What it tells us is that neither you, nor I, nor any of the DNA
companies can reliably predict how closely we are related to our more distant
cousins. So don’t rely on the testing company's estimate of how closely you’re related
to a cousin, look at the chart and figure out what's possible, then consider
what's likely (this means, for example, taking into account
your age and that of your cousin).
Even
if your DNA match is with a 5th cousin, someone who shares your great-great-great-great
grandparents, it probably won’t be obvious how the two of you are related. I
don't know about you, but I certainly can't say who all of
my 4G grandparents were - indeed, I don't even know for sure who all my 3G
grandparents were. I've got several 'brick walls' in the last 6 generations (though
fewer than before I tested my DNA) - and most researchers, including my DNA
cousins, are probably in the same situation. Go back another generation and there
are even more gaps - and it just gets worse from then on.
In
practice most of the ancestors that link us to our DNA cousins are on the other
side of a 'brick wall' - and this could be a 'brick wall' in your own tree, in
your cousin's tree, or both trees. What a fascinating challenge!
The
exclusive offer I organised with The Genealogist (see last
issue) expired on Saturday, but in response to requests from members I've
arranged for it to be extended - just click this
link. By the way, you can still
watch Mark Bayley's excellent presentation here.
Talking
of presentations, this year's competition was an experiment, but a very successful
one judging from the feedback I've had from members who were lucky enough to
attend some of the exclusive virtual events I organised for prize-winners. And for
me it was a chance to put faces to the names of some of those I've been
corresponding with for 10 years or more!
This is where any major updates and corrections will be
highlighted - if you think you've spotted an error first reload the newsletter
(press Ctrl-F5) then
check again before writing to me, in case someone else has beaten you to
it......
Peter Calver
Founder, LostCousins
© Copyright 2022 Peter Calver
Please do NOT copy or republish any part of this newsletter without permission - which is only granted in the most exceptional circumstances. However, you MAY link to this newsletter or any article in it without asking for permission - though why not invite other family historians to join LostCousins instead, since standard membership (which includes the newsletter), is FREE?
Many of
the links in this newsletter and elsewhere on the website are affiliate links –
if you make a purchase after clicking a link you may be supporting LostCousins
(though this depends on your choice of browser, the settings in your browser,
and any browser extensions that are installed). Thanks for your support!