Newsletter - June 30, 2016

North American edition

 

 

Your ancestors were immigrants

Free access to over ONE BILLION records at Findmypast ENDS JULY 6

Free access to 260m Canadian records at Ancestry ENDS JULY 3

DNA testing comes of age

Can genetic testing determine your ethnicity?

The randomness of DNA: good news and bad news

How to download your results from Ancestry

The wonders of X-DNA

Why don't my brother's results match mine?

The beautiful truth

Privacy is important

Hot news!

 

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Your ancestors were immigrants

North America is a land of immigrants - even the ancestors of Native Americans were immigrants, albeit tens of thousands of years ago. Of course, no written records exist of those early migrations - researchers have made their deductions using DNA evidence and artefacts that have survived (see this Time magazine article) - but we are blessed with some records of more recent migrations, including passenger records, naturalization records, and the Ellis Island database.

 

 

Free access to over ONE BILLION records at Findmypast ENDS JULY 6

From now until July 6 you can access over 1 billion records free at Findmypast.com, including:

 

 

 

 

 

 

There's no catch - you will be expected to register, but you won't be asked to provide credit card or bank details. To find out more simply follow this link.

 

Note: Findmypast have over 8 billion records in their collection, including the largest collection of Irish records online. Searching is always free, but to view records that aren't included in the offer will require the purchase of credits (or an appropriate subscription).

 

Free access to 260m Canadian records at Ancestry.ca ENDS JULY 3

It's Canada Day tomorrow, and until July 3 Ancestry.ca are offering free access to all 260 million Canadian records - just follow this link.

 

DNA testing comes of age

There are now around 3 million people worldwide who have taken autosomal DNA tests, most of them family historians - whereas there are less than 2.4 million with current Ancestry subscriptions. I mention these amazing statistics because many researchers still think that DNA testing is something to consider for the future. Well, the future is here!

 

Of course, making sense of DNA matches isn't easy - but then it can be a great struggle to make sense of online trees, many of which are unsourced (or, even worse, mistakenly linked to the wrong sources) and perpetuate errors by making them easy for others to copy.

 

There's a great TED talk about DNA that I watched recently. I don't usually watch online videos but this one is exceptional - so exceptional that I've embedded it in this newsletter:

 

 

DNA testing is just another way of finding cousins, so don't spend out on a DNA test until you've tried the free options, such as completing your My Ancestors page at the LostCousins site.

 

We're used to there being a trade-off between time and money, so it's natural to assume that if you spend out a large sum on a DNA test you're going to be saving yourself time - dream on! You might think that it's tedious looking up censuses and keying in data, but believe me, sorting through DNA matches and trying to make sense of them is much harder, and far more time-consuming. And, of course, it's infinitely more expensive.

 

So why use DNA at all, if it's more expensive and more difficult? Because it can tell you things about your ancestry that conventional research may never discover (because the records don't exist, or were falsified). Most importantly DNA testing can not only confirm what we know, and contradict what we think we know, it can also help to knock down seemingly impregnable 'brick walls'.

 

Best of all, the evidence is inside us - we don't have to go hunting for it!

 

Can genetic testing determine your ethnicity?

Someone asked me recently which of the DNA testing companies will provide the most meaningful autosomal results. The simple answer is - none of them! In isolation DNA results mean very little - they're just a jumble of letters - but they acquire meaning when they are compared with results from other people.

 

Of course, most DNA testing companies will claim to tell you something about your ethnicity - but as I pointed out recently, Ancestry reckon my brother's ancestry is 20% Irish, which is virtually impossible, given how far I've traced back without finding any Irish ancestors in our tree.

 

I've uploaded my brother's results to FamilyTreeDNA - they reckon he's 40% Scandinavian, 40% British Isles (including Ireland) and 20% Southern Europe; but they tell me that I'm 59% Western & Central Europe, and 41% Scandinavia. We have the same parents, so how can our ancestry be so different - of course, the answer is that it can't!

 

The truth is, DNA tests are pretty poor at telling us about our origins hundreds or thousands of years ago. One of the reasons for this is the simple fact that we haven't inherited any DNA at all from most of our ancestors!

 

Note: some the tests that 23andMe offer are designed to provide health-related information - these may have some value on their own.

 

23 Pairs of Chromosomes. One Unique You. Get your DNA story at 23andMe.com.

 

The randomness of DNA: good news and bad news

If you test your autosomal DNA you'll get hundreds or thousands of matches, and naturally you're more likely to get matches with close cousins than distant ones - since close cousins are more likely to share large segments of DNA (this page from the ISOGG website gives the statistics).

 

However, the fact that you're more likely to match with close cousins doesn't mean that most of the matches you make will be with close cousins - in reality the majority of your matches will be with cousins who are so distantly related that you wouldn't expect to share any significant amount of DNA with them.

 

How can both of those statements be true? What you have to remember is that we have many, many more distant cousins than we do close cousins - according to this article, calculations by Ancestry DNA found that on average we each have 193,000 living cousins who are 6th cousins or closer, but that almost of them are 5th (17,300) or 6th (174,000) cousins. The article doesn't give a figure for the numbers of 7th and 8th cousins, but clearly they're likely to be in the millions.

 

According to the ISOGG chart I mentioned earlier, 8th cousins share (on average), just 0.000763% of their DNA, which equates to just 0.05cM - in other words, it's such a small amount that it would be dwarfed by the DNA that is shared by chance. So, as you can imagine, I was amazed when Ancestry claimed to have found a match with an 8th cousin - a connection that was backed up by our family trees.

 

What Ancestry don't provide is any detail of a DNA match - but fortunately my cousin had uploaded his results to the GEDmatch site, and there we could see that we shared an amazing 24cM segment of DNA. A segment this length would be more typical of 3rd cousins than 8th cousins, so you might be wondering how this can happen.

 

With each generation DNA is diluted by half, since every child has two parents, each with their own set of ancestors. If you refer to the ISOGG chart you'll see that 3rd cousins are 7 degrees apart, and on average their shared DNA amounts to 1/128th (1 divided by 2 to the power of 7). Similarly 8th cousins are 17 degrees apart, so on average their shared DNA amounts to 1/131072 (1 divided by 2 to the power of 17).

 

If I tossed a coin 17 times, on average it would come up heads 8.5 times - but 1 time in 131072 trials it would come up heads every time. Those are long odds, but then we each have millions of 8th cousins, and we each have 22 pairs of autosomes (chromosomes that are inherited from both parents). So now it doesn't seem quite so surprising that two 8th cousins share such a large segment of DNA on one of those chromosomes!

 

Nevertheless, when you find a DNA match with a very distant cousin, always consider the possibility that you have another, closer, match on a different line that is yet to be found. Something else to bear in mind is that in isolated or close-knit communities where few people married outsiders the gene pool would be smaller, and this would inevitably make matches appear closer.

 

Note: amongst the useful tools at GEDmatch is one that will analyse how closely -related your parents were before they married - whilst few people knowingly marry their cousins, there must be many who do so unwittingly.

 

The fact that DNA can sometimes reach back further than expected can be good news - but it can also cause confusion if we don't take the possibility into account when we're trying to work out how we're connected to our DNA cousins.

 

How to download your results from Ancestry

To upload your DNA results to GEDmatch (or any other site) you must first download them from Ancestry or Family Tree DNA. This is very easy to do, but if you haven't done it before, this brief guide for Ancestry users will prove invaluable.

 

First look for the Settings link at the top right of your DNA home page:

 

 

When you click the button you'll be taken to the Test Settings page - look for the Download Raw DNA data area on the right:

 

 

When you click the button Ancestry will ask you to enter your password: they'll then email you a link that will allow you to download your data. It will be downloaded as a ZIP file, but there's no need to unzip it, as GEDmatch will only accept the data as a ZIP file. (And, by the way, you certainly don't need to understand the data!)

 

Uploading your results to GEDmatch is easier - simply register or login, then click the AncestryDNA link under File uploads. You'll need to know where the file you downloaded from Ancestry has been saved - usually it will be in the Downloads folder, and the filename will look something like this:

 

dna-data-2016-06-10.zip

 

The wonders of X-DNA

Some of you may have noticed that whilst I've written extensively about Y-DNA, autosomal DNA, and mitochondrial DNA I haven't talked about X-DNA up to now.

 

I intend to remedy that in this article, although I'm going to start by reminding you what all these different terms mean….

 

The term autosomal DNA refers to the 22 pairs of chromosomes that we inherit equally from our parents - one chromosome in each pair comes from our mother, one from our father. We also inherit two more chromosomes - an X chromosome from our mother and either an X chromosome or a Y chromosome from our father. These last two are known as the sex chromosomes, because they determine gender - females inherit two X chromosomes whereas males have one X and one Y.

 

At first this all sounds quite straightforward, until you remember that each of our parents inherited 22 pairs of chromosomes from their parents (our grandparents). If our parents had passed on all of the DNA they inherited we'd have four sets of chromosomes, not two (and our children would have eight).

 

If you didn't already know the answer then I'm sure you've figured it out by now - the autosomal DNA that our parents pass down to us is a mixture of their own parents' DNA, but it almost certainly won't be an equal amount from each grandparent because the process of meiosis (in which the chromosomes are mixed) is essentially random. This means if you have siblings they won't have inherited the same mix of your grandparents' DNA as you have - only identical twins inherit exactly the same DNA.

 

Mitochondrial DNA, usually referred to as mtDNA, is passed from a mother to all of her children. However, because males cannot pass their DNA to their offspring mtDNA tracks the direct female line. Sadly mtDNA is limited value to genealogists because it mutates so slowly - even if you match someone else exactly, the chances are that your common ancestor lived upwards of 500 years ago. However it can have probative value - it was mtDNA that helped to identify King Richard III

 

Y-DNA is passed by fathers to their sons - that's why it usually follows the surname, and why Y-DNA testing is the cornerstone of most surname studies. Of course, not every male with the same surname has the same Y-DNA - quite apart from adoption and illegitimacy, which remove the link between surname and DNA, very few of the surnames which survive today originated with a single individual.

 

Now we're ready to address X-DNA. X-DNA is tested as part of an autosomal DNA test, such as Ancestry DNA or Family Finder from Family Tree DNA. Because we have 22 pairs of autosomes but only one or two X chromosomes we're much less likely to get meaningful matches on the X chromosome, but when we do it can be a welcome bonus.

 

If you're female you will have inherited an X chromosome from each of your parents; if you're male you'll have inherited only one X chromosome, from your mother. You might think this makes X chromosome testing more useful for females than for males, but as with so many aspects of DNA, it ain't that simple! Here's why: if I get an X-DNA match I know with absolute certainty that the shared ancestry is on my mother's side of my tree, which makes it a lot easier to figure out who the common ancestor was.

 

Actually it's not just my father's ancestors that can be eliminated - because sons only inherit X-DNA from their mother's there are many other ancestors who can be excluded from consideration. I've adapted the Ancestor Chart that so many members find useful, to show which ancestors provide the X-DNA that a male inherits from his mother:

 

 

You can download an A4-sized PDF by clicking here (the original chart can be found here). The boxes which are shaded represent ancestors whose X-DNA hasn't been passed down to me, and the percentages shown indicate the average amount of X-DNA that each ancestor has contributed (the actual figure could be very different).

 

The pattern of inheritance is different for females - they inherit an X-chromosome from both parents - and whilst I'm sure you could work it out for yourself, I'll put together another chart in time for the next newsletter.

 

Why don't my brother's results match mine?

If you look at the chart above you'll see that I inherited 100% of my X-DNA from my mother, and of course my brother did too. You might expect, therefore, that just as our Y-DNA matches exactly (because we have the same father), so does our X-DNA.

 

Autosomal DNA and X-DNA matches are measured in centiMorgans, usually abbreviated as cM (if you're interested in finding out what a centiMorgan is, this page on the ISOGG website tells all). Segments which are more than 10cM long generally indicate shared ancestry; segments below 7cM usually match by chance (unless you and your prospective cousin also have longer segments that match).

 

But this page from the free GEDmatch site shows how little of my brother's X-DNA matches mine: the green sections are where we match, and it's likely that these are all chance matches apart from the 10.7cM section which is highlighted in blue.

 

 

How can our X-DNA be so different when we both inherited our X chromosome from our mother?

 

It's very simple - like all females our mother had two X chromosomes, one inherited from her father (our maternal grandfather), and one inherited from her mother (our maternal grandmother). Clearly one of us has inherited X-DNA that comes mainly or entirely from one grandparent, whilst the other has inherited X-DNA that comes mainly from the other grandparent.

 


The beautiful truth

Have you ever comes across the Fibonacci series? This is a mathematical function that pops up time and time again in nature, and it just so happens that it describes perfectly how many ancestors from each generation have passed their X-DNA to me.

 

Here are the first few terms of the Fibonacci series:

 

0, 1, 1, 2, 3, 5, 8, 13, 21, 34……..

 

What you will notice is that each term in the series is the sum of the two preceding terms, for example 1+1=2, 1+2=3, 2+3=5 and so on. This in itself is interesting (for some of us) but what's really important for me as a genealogist is the fact that these numbers also represent the number of ancestors from each generation who have contributed to my X-DNA.

 

If you refer to the chart above you'll see that I have inherited my X-DNA from 1 parent, 2 grandparents, 3 great-grandparents, 5 great-great grandparents, and 8 great-great-great grandparents - and whilst it's not practical to include more generations on a single sheet of A4 paper, I can assure you that there would have been 13 ancestors from the next generation (out of 64), 21 (out of 128) from the generation after that, and 34 of my 6G grandparents (out of 256).

 

Why might this be important? There are two reasons - the obvious one is that with fewer ancestral lines to consider it's usually going to be a lot easier to determine which ancestors we share with our X-DNA cousins (compared to resolving atDNA matches).

 

Less obvious, but equally important, is that because X-DNA is diluted less with each generation it has the potential to reach back further. I inherited an average of just 3.125% of my autosomal DNA from each of my 32 great-great-great grandparents, but between 6.25% and 25% of my X-DNA from 8 of them.

 

For this reason you'll often find that you don't share any meaningful segments of atDNA with your X-DNA cousins - though when you do, it's a bonus!

 

Privacy is important

Ancestry trees work well for some, but there are many people who value their privacy, and wouldn't dream of posting personal information about themselves or their family where everyone can see it. Some of those people are my cousins, and some of them are your cousins - but how could you and I hope to connect with them online given their concerns?

 

It was because of this conundrum that, when I was inspired to start LostCousins back in 2003, one of my key aims was to design a site where cousins could meet without the privacy of either party being compromised. I'm glad to say to say that it has worked amazingly well - nobody has ever complained that their privacy has been breached.

 

Hot news!

This is where any last minute updates and corrections will be highlighted - if you think you've spotted an error (sadly I'm not infallible), reload the newsletter then check here before writing to me, in case someone else has beaten you to it......

 

That's all for this issue - I'll be back soon with more news from the wonderful world of genealogy.

 

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Peter Calver

Founder, LostCousins

 

© Copyright 2016 Peter Calver

 

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