Beginner's Guide to Genetic Genealogy (DNA Testing for Genealogy)

[kwheaton]

I have an online Beginner's Guide to Genetic Genealogy that is really for beginners: http://tinyurl.com/geneticgenealogyguide

There are currently 14 Lessons and more may be added. I wrote these in response to repeated requests on the DNA Newbie List. I thought I would post here. These are FREE online and there is no homework

They are my gift back to the greater genealogy community.

They start from the beginning and try to make a complex subject understandable without too much jargon. Hope they help someone!
Kelly

[jc26red]

I will certainly take a look, after enlisting my husband to do a ydna test, I'm finding it difficult to take it in, all new info to me!

Though I might be a bit luckier than most, the surname group adminstrator is being very patient with me and explaining everything in small words, bless him!

[jc26red]

Hi again Kelly...

I like your dna guide, definitely easier to read for beginners. It has filled in one or two gaps for me.

I have a question though, you mention in one of the Y-dna lessons that having an older father could possibly account for a marker difference/mutation.  I have not read that anywhere else (I'm still learning!) and am interested in knowing where I can find the source info please.

My husband took a 37 marker ydna test with ftdna and it came back with 5 matches,  I was 95% sure that 3 were going to match as both trees had been well researched but actually knowing where they connect has not been forthcoming with paperwork, I know it was  sometime between 1641-1700 and Ireland! I say no more.
All 3, share the same surname, plus one other were just 3 single markers different and the 5th one was 4 single markers.  Now my husband's line is full of older fathers, mostly over 45, the oldest being 69 when his only son was born! Now I have read your lesson, I am wondering if that possibly a reason between my husband and the 3 I knew were going to match... they descend from 2 sons just 2 levels down from when we think our common ancestor lived, they were perfect matches (obviously a little closer  but still before 1790.

Just to make the whole dna search a little bit more interesting, ftdna came back with a result of  haplotype C.  Having read up a little bit on this group, my husband has now joined the Isogg Haplotype C project and they have projected it as C7-V20 which is quite a rare type I believe - all 5 members! my other half and one of the above matches with a different surname but also with Irish heritage plus a few Spaniards Now, this is getting a bit interesting we are going to invest in their  deeper V20 test.

Interested to hear your personal view on the paternal ages and have you found that occurance within your group or personal experience yet?

Thanks... any other administrators or dna experts please chip in if you have anything more you can share (peacefully please)

[kwheaton]

Here is alink to a journal article where this is noted.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2766043/

My husband has the most mutations in the Wheaton project in his haplotype and he also comes from a long line of older fathers and younger wives;-) Some families or haplotypes are more prone to mutations than average and the whole DNA lottery is just that. As they say " mutations happen when they happen."

The are simply replication errors and they happen randomly. Which means some families won't get any and some will get more than their fair share. The deep ancestry is interesting too!

I like to think if DNA as the encyclopedia of life stories of all our ancestors and where they have been.

[jc26red]

Thank you Kelly,

It does give food for thought, but interesting taking it on a personal level matching the two lines and being able  to analyse the differences, which, although separated by the Atlantic, followed extremely close similarities and life patterns.

Jenny

[supermoussi]

The are simply replication errors and they happen randomly.

Mutation rates are usually associated with

a) health issues like disease, malnutrition, radiation, etc
b) a genetic variance between different families

If someone is exposed to radiation or is subjected to prolonged periods of poor diet/ill health it would be expected that the number of mutations in their children would increase.

[jc26red]

Thank you supermoussi,

Gives me more to think about, of course I can only really assess our line properly. I can probably dismiss malnutrition as they were landowners to the earliest records I have and had access to very good food, they owned mills and also raised cattle for meat and dairy and deer..  illness is a possibility for a couple of the younger fathers... my FIL contracted malaria during the war (died age 54 from heart problems) and his grandfather contracted cholera in his early 20's but he went on to have a family and lived to 79, his ggrandfather died of liver disease at the age of 64 in 1853... prior to that they all lived into their 90's!   They were all very tall, which also indicates no malnutrition along the line. I'm pretty confident that there were no other known illnesses as my husband's grandfather was a doctor and passed down the family medical history from his father down!

I haven't a clue on how to assess radiation in the Irish countryside between 1650-1850 and London for the last 3 generations.

As far as I'm aware the other dose family line I'm comparing it to had very similar living conditions. 

[supermoussi]

As far as I'm aware the other dose family line I'm comparing it to had very similar living conditions.

I wouldn't worry about it too much as there is a margin of error in looking at STR results due to:-

 1) Men's Y-DNA contains several hundred STR markers and you are only looking at 37 of them! You might find you match someone on the first 37 markers quite closely but then find you are less similar on markers 37-300! If you want to get a more accurate picture of how closely related different lines are you need to test as many markers as possible. The 111 FTDNA test is the test that looks at most markers currently.

2) STR markers can back-mutate (unlike SNPs which are here forever once a family gets them), i.e. a marker can increase in value and then later decrease back again. This cannot be seen in our results so introduces a margin of error.