Testes gene may be what makes us human

News in Science ^ | Wednesday, 19 February  2003 | Bob Beale

[vannrox]

	Here is the news: a gene from the testes may be what made humans diverge from their prehistoric ancestors

The sudden emergence of an unusual new gene expressed mainly in the testes of our direct primate ancestors may have helped humans to become a distinct species, American scientists have reported.

Professor Daniel Haber, of the Harvard Medical School in Boston, and colleagues report the discovery in a study published in this week's issue of the Proceedings of the National Academy of Sciences.

They conclude that the new gene, known as Tre2, appeared as little as 21 million years ago - relatively recently in terms of human evolution - and note that "the emergence of novel genes this late in evolutionary history" had not been appreciated until now.

The gene was first identified during the human genome project, but its evolutionary origin was unknown.

Haber's laboratory specialises in the genetics of cancer, and was studying Tre2 during a routine search for unknown oncogenes, which can transform normal cells into cancerous ones.

They found that it does not cause cancer in humans, but does act as an oncogene in mice. This makes it unique among oncogenes in being a normal human gene which can cause cancer in a species that lacks it.

When they analysed the gene in detail, they discovered that it was a chimera gene: composed of fused pieces of two older genes that still exist and are expressed in many parts of the human body. Because it is expressed predominantly in the testes, the researchers believe Tre2 may well have played a role in creating the reproductive barrier that led to humans becoming a separate species.

By comparing the human genome with those of other species, they learnt that Tre2 is found uniquely in the human line of ancestry among the primates. Our ancestors seem to have been especially prone to undergoing a whole series of duplications of segments of their genes, the authors write.

"These duplications appear to have emerged only during the last 35 million years, within the primate lineage, and to have rapidly expanded," Haber said. The new gene probably emerged from that process when two duplicated segments of different genes fused to make a new one.

The researchers date that event at around the time the hominoid lineage appeared, between 21 and 33 million years ago. Its sudden emergence - and its association with the testes - may have meant that individuals who had the gene could not reproduce with those who did not.

The researchers suggest that this may have led to speciation among primates and, eventually, to the genetic differences that spawned humans. The findings highlight both a growing awareness of the striking unity between all living things, coupled with a previously unknown plasticity in the way genes evolve.

It now seems that genetic codes can change markedly over time as well: single genes can be duplicated, deleted, switched on or off, moved to different locations, fused with parts of other genes (as in the case of Tre2), or be pressed into service in new roles.

Yet many are stable and well conserved: about seven out of every 10 genes found in bacteria, for example, are now thought to be the direct counterparts of those in their common ancestors hundreds of millions of years ago.

Bob Beale - ABC Science Online

More Info?

Chimps to give genetic clues on human diseases, News in Science 17 Apr 2001

Human genome discovery brings challenges, News in Science 16 Feb 2001

Further controversy on human origins, News in Science 16 Jan 2001

© ABC 2003 | privacy

[vannrox]

Hum. Interesting.

[HEY4QDEMS]

So the next time somebody asks me "Are you nuts?", How should I answer?

[stanz]

ping

[templar]

The sudden emergence of an unusual new gene expressed mainly in the testes

Must be why mankind is referred to as Mankind.

[r9etb]

33 million years ago. Its sudden emergence - and its association with the testes - may have meant that individuals who had the gene could not reproduce with those who did not.

Hmmmmm. So if a gene mismatch is fatal, how would such a gene be passed on from the first person who had it?

[lepton]

bookmark bump

[ClearCase_guy]

I am confused. I thought that Homo Sapiens appeared about 50,000 to 100,000 years ago. I thought that "man" was traced back to "Lucy" about 6 million years ago -- and at that time we were small, primitive primates. This article is saying that the gene event occured in hominids about 20-30 million years ago.

Lucy, you got some 'splainin' to do.

[LiteKeeper]

read later - All of our God-given DNA is what makes us human - it is He who gives life and breath to all.

[Sacajaweau]

Think he's looking for grant money based on something "new" that can never be proved???

[Sacajaweau]

Professor Dan says "It took "ba***" to start the human race".

[PatrickHenry]

Family jewels ping.

[This ping list is for the evolution -- not creationism -- side of evolution threads, and sometimes for other science topics. To be added (or dropped), let me know via freepmail.]

[unixfox]

Well, this settles it. There is no God or higher being. We just simply evolved.

[f.Christian]

Evolution (( overlords )) is -- full on -- brainwashing (( redacting // deleting -- HATING God -- conservatism )) and . . .

indoctrinating // programming LIBERALISM -- LOVING LEFTIST lies // bias -- all through America // society ! ! !

All unashamedly on the FR too ==== "fraud // corruption" ==== UNADULTERED tyranny // blasphemy -- slavery !

Aids of the soul // society === America !

[BeAllYouCanBe]

"The researchers suggest that this may have led to speciation among primates and, eventually, to the genetic differences that spawned humans. "

I MAY BE A MONKEY'S UNCLE!

Like every other article on this subject the writer uses; may have, could have, possibily have, and the top of all the politically correct evolution words "most likely" to have been caused.(Why can't they say they just don't know?)

Wake me up when they know what is going on.

[Lurking Libertarian]

Well, this settles it. There is no God or higher being. We just simply evolved.

Wha???

Evolution is completely compatible with a belief in God. God created us; evolution is how He did it.

[f.Christian]

religious holiday for the god (little g) of Darwin worshippers. It would be sort of like Kwanza for "scientist".


278 posted on 02/14/2003 8:35 PM PST by Busywhiskers

Show // tell -- whacky liberal 'science' !

[Physicist]

This article is saying that the gene event occured in hominids about 20-30 million years ago.

The article said hominoids, not hominids. The term "hominoid" comprises the apes as well as the hominids.

[Dimensio]

He's joking.

[JoJo Gunn]

Everybody quit the bickering and LISTEN UP! Cup your ears and you'll hear the unmistakeable sounds of razor blades sliding across the wrists of the N.O.W.freaks....

[ricpic]

"Balls" said the Queen, "if I had them I'd be King."

"Nuts" said the Jack, "a lot of good they've done me."