Comments for gcbias

Comment on European genealogy FAQ by Tamara Tomaschow

Tamara Tomaschow — Thu, 16 May 2013 23:15:49 +0000

Thanks so much for the links!

Comment on European genealogy FAQ by Pejman Yousefzadeh

Pejman Yousefzadeh — Wed, 15 May 2013 22:54:53 +0000

What about Iranians? Jews? Iranian Jews?

Comment on European genealogy FAQ by cooplab

cooplab — Tue, 14 May 2013 16:25:03 +0000

Hi Tamara. Thanks for your question. A couple papers that may be of interest are:
Bryc et al. PNAS 2009 http://www.pnas.org/content/107/2/786.long
Kidd et al AJHG 2012 http://www.ncbi.nlm.nih.gov/pubmed/23040495

A blog post from 23&me on African American ancestry
http://blog.23andme.com/news/large-study-reveals-details-of-african-american-genetic-ancestry/
that discusses the results of Bryc et al.

Comment on European genealogy FAQ by Tamara Tomaschow

Tamara Tomaschow — Tue, 14 May 2013 16:08:55 +0000

What about African Americans? What works can I review that may help shed some light on the many places that my genetic markers can be traced back to??

Comment on European genealogy FAQ by petrelharp

petrelharp — Mon, 13 May 2013 18:22:19 +0000

Bottlenecks, in general, would increase shared ancestry coming from the time of the bottleneck. Intuitively, this is because everyone picks their ancestors from a smaller pool, so there has to be more sharing.

However, the strength of the bottleneck depends on both how much the population contraction and how long the population stayed small for. Black Death, if I understand correctly, reduced the population by at most 50%, but only lasted for about a generation (any one bout did, anyhow). Cutting the population in half would increase the chance of sharing an ancestor from that generation by a factor of 2. If we had single-generation temporal resolution, then we coudl maybe see that. But, the temporal resolution is between 10 and 20 generations, and spreading that brief increase over 10 generations results in not a very noticable bump.

Also, since the black death was relatively recent, we don’t have much ability to see it. We get few common ancestors from the last 1000 years (because of larger populations, and fewer potential ancestors), and twice a really small number is still really small.

Comment on Population genetics course resources: Hardy-Weinberg Eq. by Nadia S.

Nadia S. — Mon, 13 May 2013 12:14:18 +0000

This is terrific, Graham! I used these HWE figures in my lecture on human population genetics a few weeks ago. So helpful! Also, my students just took their final exam and one of the extra credit questions was ‘what is the most interesting thing you’ve learned in the course?” A solid 1/3 of the class said that these plots were their favorite thing. One student even said it blew her mind!! I guess I’ll be using them every year!!

Comment on European genealogy FAQ by Identification of genomic regions shared between distant relatives | gcbias

Identification of genomic regions shared between distant relatives | gcbias — Fri, 10 May 2013 16:03:48 +0000

[…] in Europe is related to nearly everyone else over the past 1000 years (see our recent paper and FAQs), and likely everyone in the world is related over the past ~3000 years, how should you interpret […]

Comment on European genealogy FAQ by Indentification of genomic regions shared between distant relatives | gcbias

Fri, 10 May 2013 16:02:24 +0000

Comment on European genealogy FAQ by What we’re reading: Evolutionary context for disease markers and why everyone has at least one famous ancestor | The Molecular Ecologist

Fri, 10 May 2013 13:02:47 +0000

[…] also: the authors’ FAQ on the article and very nice discussion by Carl […]

Comment on arXiving our papers by Peter and I’s European genetic genealogy paper is out. | gcbias

Peter and I’s European genetic genealogy paper is out. | gcbias — Fri, 10 May 2013 00:53:58 +0000

[…] the paper to PLOS Biology (in July 2012). I’ve written about our reasons for doing that here, and blogged about the paper here at Haldane’s sieve. The arXived paper has gathered a number […]