Need Help Developing Biology-Evolutionary Explanations for Sex Chromosomes
I have an idea that the Y chromosome is the location for the development of new genes. I say this because I read there are 4.8 times more mutations there than other chromosomes. Also many more inversions and duplications occur there than elsewhere on the genome. Finally I read that the human Y chromosome is much different than the Chimpanzee one, and is the least analogous to its comparable chimpanzee chromosomes.
My speculation is new genes are made on one end of the Y chromosome and if they survive sexual, environmental and other selection pressures, there is a time keeping process. That time keeping is carried out by a system of gene travel along the structure from the one end of where genes are created, i.e. "the starting line" to the other end, "the finish line". If after a bunch of generations, the gene makes it to the finish line, than it appears to the organism to be a possibly successful addition to the gene arsenal and is moved to the X chromosome. On the X chromosome, more refining mutations occur.
So I'm suggesting that there should be a higher amount of mutations than normal on the X chromosome just like Y, but of a less wholesale variety. The mutations on the X might be more of the point variety.
The analogy is a master sculptor and his apprentice. The apprentice works as the Y chromosome in getting the raw material together and gradually creating the rough outlines of what the sculptor wants. First he takes off big pieces and later takes smaller and smaller ones off until the rough shape appears. So also note analogously perhaps, bigger changes are allowed on the "starting end" of the chromosome, and lesser ones at the finish line.
The X chromosome is analogous then to the master sculptor who takes over the work and makes tiny changes to bring out the finished work which is then transferred to a museum.
Perhaps more appropriately instead of a sculpture, the master and his student are working on coin dies that will be used to stamp out coins.
At any rate my idea needs:
- References.
- More reasons why this mechanism is plausible.
- A teasing out of the logic that makes it worthwhile for an organism to try out new genes all by themselves on the Y chromosome. These Y chromosome genes are expressed in one half of all offspring, mainly the males. When the gene proves good enough to move to X chromosome, why is it beneficial for refining mutations to then be exposed by themselves only in one quarter of the offspring, again in males? This question arises because genes on the X chromosomes have backup copies to bail them out of trouble in females. The further mutated genes would show up on the X chromosome in only half the males because the other half would receive a non-mutated one from their mother. Is the one quarter expression meant to conserve the promising new gene? How would this outweigh masking of faulty refining mutations to genes in females?
- How crossing over not occurring in the sex chromomes, makes sense in this scheme.
- Refutation of nay-saying for instance that the sex chromosome just code for sexual organs or that for instance the Y chromosome is found in the female in the fruit fly and the male has the X. In other words reasons why this explanation might be justified despite exceptions to the rule that the male has a Y chromome in organisms and the female has an X.
Thanks much :-))