Modern men lack Y chromosome genes from Neanderthals


#1

From today’s Science News:

Although it’s widely known that modern humans carry traces of Neanderthal DNA, a new international study led by researchers at the Stanford University School of Medicine suggests that Neanderthal Y-chromosome genes disappeared from the human genome long ago.

The study will be published April 7 in The American Journal of Human Genetics, in English and in Spanish, and will be available to view for free. The senior author is Carlos Bustamante, PhD, professor of biomedical data science and of genetics at the School of Medicine, and the lead author is Fernando Mendez, PhD, a postdoctoral scholar at Stanford.

The Y chromosome is one of two human sex chromosomes. Unlike the X chromosome, the Y chromosome is passed exclusively from father to son. This is the first study to examine a Neanderthal Y chromosome, Mendez said. Previous studies sequenced DNA from the fossils of Neanderthal women or from mitochondrial DNA, which is passed to children of either sex from their mother.

Other research has shown that the DNA of modern humans is from 2.5 to 4 percent Neanderthal DNA, a legacy of breeding between modern humans and Neanderthals 50,000 years ago. As a result, the team was excited to find that, unlike other kinds of DNA, the Neanderthal Y chromosome DNA was apparently not passed to modern humans during this time.

sciencedaily.com/releases/2016/04/160407132318.htm


#2

[quote=from article]Theoretically, said Mendez, a woman’s immune system might attack a male fetus carrying Neanderthal H-Y genes. If women consistently miscarried male babies carrying Neanderthal Y chromosomes, that would explain its absence in modern humans. So far this is just a hypothesis, but the immune systems of modern women are known to sometimes react to male offspring when there’s genetic incompatibility.
[/quote]

This is what I think is the reason.


#3

I wonder if Neanderthals were slightly genetically different that the offspring would be sterile? Like mules and ligers? But then it wouldn’t explain how the DNA would carry on until now.

I recently had my DNA tested, and I have slightly higher rate of Neanderthal DNA. :blush:

My mitochondrial DNA also originates in Ireland and Poland.

I’m ethnically Sicilian though, so I wonder how that happened. Most of the people that match me on the DNA site are Irish.


#4

I don’t know your ancestral tree any better than you do. But it may be noted that Normans occupied Sicily for some time during the Middle Ages. Supposedly Normans are Danes who invaded and settled Normandy. Thence they went to England. But there is a lot of “Norman” intermixture in Ireland. The Irish side of my family has a Norman name.

“Norman”, however, simply meant “North men”. One notes that the Varangian Guard, generally considered Scandinavian, were “North men” of all sorts, including Brits, Irish, Scots and Continentals as well as Scandinavians.

There is a Celtic part of Poland called Galizia, and I’m sure there is plenty of intermixture in northern Poland. Teutons and Celts are thought of as different peoples, but they are more alike than they’re different.

Neanderthal physiologic traits are found more in northern Europe than anywhere else.

Oh yes, and at various times, the Roman army had whole legions composed of various peoples like Gauls or Teutons. During Jesus’ time, the Roman legions in Syria were composed of Germanic soldiers; something that has lingered on in the DNA of people there and in Palestine.


#5

The European ethnic bloodlines got royally shuffled around over the generations; long before their descendants settled in NA (whose people are notorious for being human mutts).

Shaking head at the reasons for ya’lls obsessive ethnic pride. :slight_smile:

ICXC NIKA


#6

Interfertility isn’t always binary, and it can be more complex than even differing chromosome counts. It is possible that Neanderthal-human hybrids were less fertile, but there was still enough fertility to allow a certain amount of the Neanderthal genome to end up in modern humans in Eurasia and North Africa.

As to it ending up in Sicily, probably from the Goths, and later the Normans.


#7

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