Comments on: Tracing my roots

By: michael enns

michael enns — Tue, 17 Mar 2009 01:06:53 +0000

I have researched my ancestry, and have traced it back to the early 1700′s, and have found out that there is no deterrent from a branch of Mennonites who lived together in villages. There were no outsiders that came in from elsewhere. Marriages were arranged, and the Mennonites began in North western Holland. From there, they went to Danzig, Poland, where they lived from about 1560 to 1800, and because of persecution, again, they had to travel to the eastern steppes of Europe, in the Ukraine. They stayed there until 1875, when once again, enlistment in the war became mandatory, so they traveled to North and South America. My mother’s family went to Pennsylvania, and shortly thereafter, moved to Alberta. My father’s family went to Manitoba, and soon went to Alberta. My parents met in Alberta, and I was just wondering how such untainted history might be of interest to the subject of DNA study. As far as I can tell, there has been untainted Mennonite blood in my history for at least 500 years.Before that I don’t know, but some say that Europe was started by a group of about 50 people.

By: jasmine

jasmine — Wed, 26 Apr 2006 16:49:01 +0000

advice is given to everyone by only the wise benfit me

By: fadereu

fadereu — Thu, 04 Aug 2005 16:11:27 +0000

I have met Spencer in Bombay when he released his book The Journey of Man herea, and he's a really cool guy,a very clear-headed geneticist.

My point is this: Do I need scientific evidence (continent of origin, shared DNA) that IÂ’m connected with all other humans to be a thoughtful and progressive human being? Unless youÂ’re a religious zealot or still subscribe to chosen people myths, I would hope the answer is no.

You may not,but once you discover just how many people are religious zealots, you'd agree with Spencer.

If Wikipedia is aiming to be the sum of human knowledge available to humanity, Spencer is aiming at proving to us that we all descend from one man who lived 60,000 years ago in Africa.

Think about it. Someday you'll be producing his study in court as evidence against racial discrimination.

Respect when its due.

By: brimful

brimful — Thu, 04 Aug 2005 02:47:59 +0000

Yamini, the basic theory about the extinction of the Y chromosome is that there is only one of its kind in every pair of mammals (male, or XYs, as brimful likes to call us, and females, or XXs that is producing an offspring.

Rahul, in all fairness, I shamelessly stole the usage of XY from a certain Amelie-Freak… well, and biologists everywhere.

By: nivritti

nivritti — Wed, 03 Aug 2005 21:27:38 +0000

for those who want more complete information on the process of recombination of the sex chromosomes and the decay of the y chromosome:

http://en.wikipedia.org/wiki/Y_chromosome

yes, i was procrastinating at work .

By: Rahul

Rahul — Wed, 03 Aug 2005 09:57:35 +0000

And, of course, the fact that I am posting about Y chromosome recombination at 4 AM is another piece of evidence for my unsullied state. Now for that scholarship, Mr. Sulaiman Madada.

By: Rahul

Rahul — Wed, 03 Aug 2005 09:54:04 +0000

Yamini, the basic theory about the extinction of the Y chromosome is that there is only one of its kind in every pair of mammals (male, or XYs, as brimful likes to call us, and females, or XXs that is producing an offspring. Hence, the Y cannot be repaired by recombination with X, except at its tips, during sexual reproduction or meiosis (because, recombining with X could mean that the Sex-determining Region on the Y -SRY – could get swapped with the X, removing the distinction between the sexes). In fact, the prevailing theory was that the Y chromosome is a genetic wasteland because many genes on the Y chromosome have become irreparably damaged over time, and that the Y has only around 20-40 genes on it.

The SRY gene, which is believed to trigger the change of female babies to male early in the embryo development phase, is basically a master switch that turns on a bunch of other genes in several pathways involved in production of a variety of hormones etc. To date, the only mammal known that does not have an SRY (and hence, Y chromosome) is the Armenian vole, which seems to have lost it at some point in its evolutionary history, and instead seems to have figured out how to turn genes on later in this pathway without an SRY (the mechanism is not understood). Thus, the Armenian vole has males without the Y chromosome, and this risk of extinction, and this seemed like the only escape route for human males too.

Having said all that, the sequencing of the Y chromosome has provided recent new information that is changing the way scientists think about this. First, the Y chromosome is now believe to have around 78 genes in it, far more than the original belief. Additionally, all the legitimate genes in the Y chromosome seem to be on palindrome sequences on the Y chromosome, which means that the Y can repair itself by the neat trick of exchanging sequences with itself. Maybe, this is what Woody Allen meant when he said about something else – at least it is sex with someone I love!

By: manju

manju — Wed, 03 Aug 2005 07:54:46 +0000

I propose only M-20s be allowed to post here. Yes everyone has to take a test and prove they are M-20s with American accents!

I suppose, even M-52 and M-69s should also be allowed to post here. Another 50% population in South India belong to these to markers, I think.

By: razib_the_atheist

razib_the_atheist — Tue, 02 Aug 2005 23:31:25 +0000

what are some of the tests and methods used to determine a marker was an independent mutation?

from what i recall they usually look closer at the nucelotide structure. also, there are sometimes nearby sequences of the genome that have "hitchhiked" along with the allele in question in population A where allele 1 is common.

By: runnerwallah

runnerwallah — Tue, 02 Aug 2005 23:18:26 +0000

we don't even know if it is an independent mutation (though usually there are ways to figure that out).

Interesting - what are some of the tests and methods used to determine a marker was an independent mutation? Interested in reading more.