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Paint_It_Black
12-21-2006, 12:04 AM
http://news.yahoo.com/s/nm/20061220/sc_nm/britain_dragons_dc

I found this to be very interesting, though one thing about it left me confused.

"The genetics of self-fertilization in lizards means that all her hatchlings would have to be male."

Why is that? I would have expected the opposite to actually be true.

XYlophonetreeZ
12-21-2006, 01:07 AM
It's because the term "self-fertilization" is misleading. There really isn't any "fertilization" per se. Sure, I guess the female's able to make herself "fertile," but there's never any fusion of gametes. Some species that normally reproduce sexually can reproduce with no fertilization, and in that case the offspring do all have to be male, but they're unusual in that the males are haploid (just one set of chromosomes). I've only heard of it happening in insects, but I guess it can happen in reptiles too. For example, that's the dilly-o with drone bees and ants. I think they just have to be male because "female" is defined as having two X chromosomes, and having two sex chromosomes of any kind is impossible in haploids.

Paint_It_Black
12-21-2006, 02:28 AM
Ok, I'm following that. So, if the definition of a female is having two X chromosomes, what's the definition of a male? Everything else? Or does a Y chromosome need to be involved? And if a Y chromosome needs to be involved, where's it coming from?

Sorry for knowing practically nothing about genetics.

H1T_That
12-21-2006, 05:30 AM
Ok, I'm following that. So, if the definition of a female is having two X chromosomes, what's the definition of a male? Everything else? Or does a Y chromosome need to be involved? And if a Y chromosome needs to be involved, where's it coming from?

Sorry for knowing practically nothing about genetics.

I'm pretty sure to be male you need a Y chromosome. I could be wrong though, i'm going off memory from 3 years ago when i last did anything to do with biological science.

Little_Miss_1565
12-21-2006, 06:09 AM
omfg RAPTOR JESUS

http://xs63.xs.to/pics/06020/raptorjesuslolz.jpg

Endy do you realize this is the #2 hit on Google images for Raptor Jesus?

nieh
12-21-2006, 06:22 AM
Females are XX and males are XY. Most animals need at least one X chromosome to survive. Since Y chromosomes are shorter, they don't have all the genes that are included on the X chromosome and some of those are needed to live and function normally. Like Richard said, I'd expect the offspring to be female, or at least appear to be female with only a single X chromosome. Unless of course the mother is actually an XXY "female" which could explain why it's possible for it to fertilize herself.

Semi-related: something like 1 in every 100,000 human females has the ability to produce both working sperm and egg. The odds of them ever actually fertilizing themselves is almost impossible but it's still there. Kind of makes some religious mythology a little more interesting.

Paint_It_Black
12-21-2006, 07:51 AM
Thanks Josh. This stuff fascinates me, in a strictly amateur way.