tesla writes
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how does chromosomes have anything to do with how evolution and adaption works?
Everything. Centromeres control cell division and gene expression, you know.
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your trying to look at 2 objects of similar form then ask why they arnt identical?
Huh?
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since when does chromosomes only add or subtract in evolution?
But in this particular case, the chromosomes didn't add or subtract.
Let me be overly simplistic to get us started. Every normal chromosome has a centromere in the center that controls gene expressions and cell division and two telomeres, one at each end, to prevent gene loss during cell division and DNA replication. If a chromosome is missing a telomere, everytime a cell divides it would lose some genes at the end of the chromosome that's missing the telomere. This would ultimately result in the partial, if not total, deletion of the chromosome and loads of genetic material. The telomeres also prevent the chromosomes from accidently fuse together.
In apes, there are 24 chromosome pairs, totalling in 48 chromosomes. Each one of these chromosomes has a centromere in the center and 2 telomeres, one at each end. What puzzled scientists back in the 80's and 90's is that even though humans are almost genetically identical to the apes we only have 23 pairs of chromosomes, totalling in 46 chromosomes. The hypothesis was that at some point in the past a telomere was deactivated resulting in the fusing of 2 chromosomes. This hypothesis was later confirmed by the discovery of 2 centromeres and 4 telomeres in chromosome #2 in humans. 1 of the centromeres is there but inactive. 2 of the telomeres are in the center of the chromosome and also inactive.
Do you understand the implication of this discovery? Centromeres and Telomeres are very much central to the issue.
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it is just as logical that a chromosomes was lost, as a chromosome was added.
No, it is not. Each chromosome carries a rediculous number of genetic material programming for everything from hair color to the size of your feet to the number of your wisdom teeth and so on. Losing a pair of chromosome in such a short time period like 4 thousand years, or having a whole new pair of chromosome in that time, is unimaginable.