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"Death of Y may spawn new human species Judy Skatssoon ABC Science Online Thursday, 10 August 2006 The chromosomes we have today may not be the ones we'll have in 15 million years. So, what will this mean for the future of our species? (Image: iStockphoto) The pending demise of the Y chromosome could give rise to a whole new species of human, a professor of comparative genomics says. Scientists have been speculating about the demise of the Y chromosome for some years now but Professor Jenny Graves of the Australian National University in Canberra has come up with a bold new twist on the theory. Graves, who has been working on sex chromosomes in marsupials, will present her theory at the 11th International Congress of Genetics in Brisbane today. She will tell the conference that new 'male making' genes on other chromosomes could step up to do the job of the Y chromosome's SRY gene, which is the key to making males male. But this could mean men without Y chromosomes would split off from those with, eventually evolving into a new species of hominid. "It's quite possible that you could make new hominid species that way," she says. When two populations become two species Graves says men without a Y chromosome would be largely infertile. But a small number would reproduce and pass the new sex determining gene to their children. Eventually the group with the new gene would separate from the Y gene group, potentially evolving into a new species, she says. "[The two groups] couldn't mate with each other so they'd get gradually different, just like chimpanzees and humans gradually became different 5 million years ago," she says. "When two populations become two species there's generally there's some sort of wedge driven between them so they can't mate with each other. "It might be a mountain range ... but it might be something fundamental like the way they determine sex has flipped to some new way." 15 million years and counting Graves says there are only 45 genes left on the Y chromosome from "a grand total" of 1400. It also contains a lot of 'pseudo genes', which look like they should work but don't, suggesting they've recently become defunct. According to her projections the Y chromosome will disappear altogether in 15 million years. This will occur because unlike the other coupled genes, the single Y chromosome can't recombine with a matching partner and refresh itself. Mutations will build up and the mutated genes will eventually drop off the chromosome because they no longer perform any useful function. Graves says this has already happened in the case of the mole vole, an aggressive little rodent that appears male and is able to reproduce despite having lost its Y chromosome. XX men Australian researcher Professor Andrew Sinclair, of Murdoch Childrens Research Institute, is researching so-called XX men, or the roughly one in 150,000 men who are born without a Y chromosome. "What it's pointing to is the presence of new genes we haven't yet discovered to replace the ones on the Y chromosome," Sinclair says. Alternately, the "volume" of previously existing genes may have been "turned up" in the absence of the Y genes, he says. Sinclair's team is the first in the world to use new high-density gene chips to examine XX men in the hope of finding out which genes these are. About 10% of affected men also have a tiny portion of the Y chromosome stuck on their X chromosome which carries across the testis determining gene, he says. Sinclair says Grave's theory about a new human species could make sense "in a theoretical way" but is unlikely in reality. "I don't know about a whole new species of human but if you lost the Y chromosome completely males would have to evolve in some way to deal with it," he says. "If you have males without a Y chromosome I don't think I'd go as far as calling them a new species, but a new type of individual." "

http://www.abc.net.au/science/news/health/HealthRepublish_1710838.htm

8/10/2006 11:42:45 AM

We'll all kill each other first.

8/10/2006 11:48:19 AM

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"We'll all kill each other first."

Truth.

8/10/2006 12:00:46 PM

see what being metrosexual is doing to our species

8/10/2006 12:04:40 PM

that's a pretty cool article

8/10/2006 12:06:43 PM

Isn't going to happen. The Y-chromosome has been sequenced several times, and it's clear that there are 78 gene 'groups' on it, many of which are still autosomal. A mechanism by which it maintains those genes wasn't discovered until a couple years ago, but it seems pretty solid.

There are several copies of each functional gene. Whenever a copy degrades, it is overwritten using the other copies as a template, during meiosis.

8/10/2006 12:07:40 PM

Marsupials scare me.

8/10/2006 12:13:49 PM

We will evolve into Bjork.

8/10/2006 12:21:39 PM

I wonder if the same is likely for species with ZZ/ZW chromosomes where ZZ = male, with females disappearing? Is the 15 million year estimate based on how many generations it'll take for the Y chromosome to become obsolete or is that figure more like a time bomb display? ;p

8/10/2006 12:24:11 PM

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"[The two groups] couldn't mate with each other"

Hahaha yeah right, if the internet is around there, the two groups WILL be fucking.

8/10/2006 12:26:50 PM

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""We'll all kill each other first.""

if we dont, we will become 2 different groups, then we'll kill each other in an all out war

[Edited on August 10, 2006 at 12:38 PM. Reason : .]

8/10/2006 12:38:20 PM

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"I wonder if the same is likely for species with ZZ/ZW chromosomes where ZZ = male, with females disappearing? Is the 15 million year estimate based on how many generations it'll take for the Y chromosome to become obsolete or is that figure more like a time bomb display? ;p"

Time bomb. In the past 6 million years, after the last autosomal addition to the Y, no genes were lost. Generally, the longevity of members of a species, and the rate at which they reproduce, correlates to the size of the Y-chromosome.

Short lived species with large litters have small or nonexistant Ys. Longer lived species with only a few offspring have large Ys. The benefits of having extra autosomal genes on the Y are more apparent. It has a greater impact on fertility.

And yes, the ZZ/ZW system is exactly the same. Some have Z0, some have ZZW, or ZW, or ZWW. Depending on the bird's sexual evolution, it may have lost the W altogether, or kept it, or gotten extra W's. Pretty much the same situation.

8/10/2006 12:42:41 PM

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""When two populations become two species there's generally there's some sort of wedge driven between them so they can't mate with each other."

tell that to the gay flight attendant who kicked boots with a primate and brought back AIDS

8/10/2006 2:34:32 PM

thats pretty sweet

8/10/2006 2:37:25 PM

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"Isn't going to happen. The Y-chromosome has been sequenced several times, and it's clear that there are 78 gene 'groups' on it, many of which are still autosomal. A mechanism by which it maintains those genes wasn't discovered until a couple years ago, but it seems pretty solid. There are several copies of each functional gene. Whenever a copy degrades, it is overwritten using the other copies as a template, during meiosis."

correct


and SIV -> HIV leap probably occured from butchering or eating a monkey rather than sex with it...

8/10/2006 2:47:52 PM

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"We'll all kill each other first."

*Insert science fiction theory here* and will happen in 15 million years.

I'm curios, any geneticists out there know of studies on other species where this effect has already occurred?

8/10/2006 3:20:39 PM

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"And yes, the ZZ/ZW system is exactly the same. Some have Z0, some have ZZW, or ZW, or ZWW. Depending on the bird's sexual evolution, it may have lost the W altogether, or kept it, or gotten extra W's. Pretty much the same situation."

-Schuchula

[Edited on August 10, 2006 at 3:31 PM. Reason : And I have a retarded cockatiel to prove it.]

8/10/2006 3:30:42 PM

I bet hillary clinton is behind this.

8/10/2006 3:34:33 PM

It we be a supermale

8/10/2006 3:37:59 PM

this could be the DUMBEST article EVAR written

8/10/2006 5:43:15 PM

We'll all kill each other first.

8/10/2006 5:45:02 PM

Seriously, if our species cant figure out how to prevent this from happening with a 15 million year head start on it I dont know if our species deserves to evolve.

8/10/2006 7:45:37 PM

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"Edited on August 10, 2006 at 3:31 PM. Reason : And I have a retarded cockatiel to prove it."

Cockatiels still have W chromosomes. As do most birds. Try again.

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"and SIV -> HIV leap probably occured from butchering or eating a monkey rather than sex with it..."

[Edited on August 10, 2006 at 8:08 PM. Reason : there's evidence that polio vaccine research caused the SIV -> HIV jump, but it's not certain]

8/10/2006 8:03:40 PM

did u know that a shorter Y chromosome usually means a larger penis?

8/10/2006 8:05:17 PM

what do you think is responsible for metrosexuals?

8/10/2006 8:06:19 PM

^^^ That's OK. None of my cockatiels are retarded in the clinical sense.

8/10/2006 8:31:18 PM

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"We will evolve into Bjork."

That would be DEvolving.

8/11/2006 1:19:57 AM

8/11/2006 1:24:38 AM