Be like rodents or die - Men face extinction

According to the Telegraph we men are on the road to extinction as the number of genes on our Y chromosome shrink and fade away.

Mercifully we are not looking at the year after next but according to researcher Professor Jennifer Graves the Y chromosome is dying and could run out within the next five million years.

In a lecture, entitled The Decline and Fall of the Y Chromosome and the Future of Men at the Royal College of Surgeons (RCSI) in Ireland, Professor Graves sad: "You need a Y chromosome to be male," she said “Three hundred million years ago the Y chromosome had about 1,400 genes on it, and now it's only got 45 left, so at this rate we're going to run out of genes on the Y chromosome in about five million years. The Y chromosome is dying and the big question is what happens then."

The male Y chromosome has a gene (SRY) which switches on the development of testis and thus determines maleness. She said it was not known what would happen once the Y chromosome disappeared. "Humans can't become parthenogenetic, like some lizards, because several vital genes must come from the male," she continued. "But the good news is that certain rodent species - the mole voles of Eastern Europe and the country rats of Japan - have no Y chromosome and no SRY gene. Yet there are still plenty of healthy male mole voles and country rats running around. Some other gene must have taken over the job and we'd like to know what that gene is."

Professor Jennifer Graves said men may follow the path of a type of rodent which still manages to reproduce despite not having the vital genes that make up the Y chromosome.

Given the number of women who consider men to be rats then that should not be a problem!

Egil the Scally and Irish Basques

Photo Hunt is the next post

There was an interesting item in Monday’s Guardian. A genetic survey of men living in the Liverpool area indicates that they have Viking ancestors.

The research focused on people whose surnames were recorded in the area before its population underwent a huge expansion during the industrial revolution. Among men with these "original" surnames, 50% have Norse ancestry. The find backs up historical evidence from place names and archaeological finds of Viking treasure which suggests significant numbers of Norwegian Vikings settled in the north-west in the 10th century.

The researchers used historical documents, including a tax register from the time of Henry VIII, to identify surnames common in the region. They then recruited 77 male volunteers with "original" surnames, and looked for a genetic signature of Viking ancestry on the Y chromosome. They report in Molecular Biology and Evolution that a Y chromosome type, R1a, common in Norway, is also very common among men with original surnames.

This is a very interesting discovery. Archaeological evidence eg the longboat recently found, rather rediscovered, at the Railway Inn in Meols on the Wirral and the place names in the area (Kirby, Thingwall etc) are an indication that the area was settled by Vikings.

In 2001 there was a fascinating series called Blood of the Vikings which looked to see if the Vikings had left a genetic trace in the British population Over 2,000 DNA samples were taken from people across the British Isles. The results found that a significant percentage of men in the Orkneys and the Shetlands have Viking ancestry (no surprise there; the islands were under Danish control until 1469 and the indigenous language, Norn, didn’t die out until the end of the 18^th century. The picture in England wass very difficult, however: Only Penrith in Cumbria was any significant race of Viking DNA found. The tests done in and around the Wirral found virtually no trace at all. It would seem that this new survey has discovered evidence missed by the earlier search focussing on a narrower sample.

The DNA survey conducted for the programme were the subject of a paper by Cristian Capelli et al of University College London called A Y Chromosome Census of the British Isles . Showed that the indigenous Britons were not totally supplanted by the Saxons except at the Cornish and Welsh fringes. Many people in England have indigenous ancestors, although the number dues rise as you head west. Also the DNA samples of indigenous Britons are very similar to those in Ireland. This would have indicated that a lot of Britons have Celtic ancestors. However, there is a marked similarity between “Celtic” DNA and Basque DNA. This would indicate that the people described as Celts were not Iron Age immigrants but have been in the islands for many millennia. If this is the case then Celtic influences were more likely to have come via through cultural transmission. But that is a whole different post