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Topic:
A math problem
Replies:
6
Last Post:
Mar 15, 2013 8:06 PM




Re: A math problem
Posted:
Mar 15, 2013 4:34 PM


On 03/15/2013 01:07 AM, Martin Phipps wrote: > Let's imagine that we are the grand designers of life. Animal life as > we know it consists of two sexes, male and female. This is, > presumably, the most efficient way of mixing the chromosomes amongst > different creatures, one male and one female, so that the offsping are > immediately different from either of the parent, thus speeding the > process of evolution. > > While this may be the most efficient way to mix chromosomes, one might > ask if it were the only way. What if instead of two sexes, one with > two X chromosomes and the other with an X and a Y chromosome, we > instead had various sexes due to a combination of chromosomes. The > simplest situation to imagine would involve two chromosome pairs > instead of one: for instance we could imagine that to be male would > require one to not only have an X and a Y chomosome but also a W and a > Z chromosome whereas females would have either two X choromosomes or > two W chromosomes. > > Well, did the math: the first generation would have males with the > XYWZ chromosomes breeding with females with either XXWW, XXWZ or XYWW > chromosomes. Alas if males breed with females with either Y or Z > chromosomes then they can get offspring with two Y chromosomes or two > Z chromosomes. These offspring would be either male (YYWZ or XYZZ) or > female (YYWW or XXZZ). > > It gets even more complicated when all the different types of males > breed with all the different types of females. For example, the males > with two Y chromosomes or two Z chromosomes breed with females at > random then they have mostly males. Indeed, I calculate if there were > an equal number of such males and a equal number of regular males as > well as an equal number of females with either two Y chromosomes or > two Z chromosomes and females with neither a Y chromosome or a Z > chromosome then what you would get, all things otherwise being equal, > is an equal number of males in females born as a result. > > Basically then I just considered two generations and already there's > an indication that there would eventually be an equal number of males > and females. I'm wondering if this is inevitable. I mean, if you > separate people into male in female based on their chromossome makeup > are you eventually going to get a 50% male and 50% female population? > > It isn't really a biology problem: it's a math problem and maybe it > has already been effectively solved elsewhere. > > Martin >
Fungi can have many genders: "Scientists discover why fungi have 36,000 sexes" (and humans not)
The Independent, 15 September 1999:
< http://www.independent.co.uk/news/scientistsdiscoverwhyfungihave36000sexes1119181.html >
David Bernier  $apr1$LJgyupye$GZQc9jyvrdP50vW77sYvz1



