Among the great apes, humans have 23 pairs of chromosomes, and the great apes ha

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Among the great apes, humans have 23 pairs of chromosomes, and the great apes have 24 pairs. Given that we share an ancestor with the great apes scientists have hypothesized that the reduction in chromosomal number for humans occurred either by the deletion of a homologous pair or by two chromosomes fusing together. Which hypothesis do you think is more likely and how might you test your hypothesis? 7. We have learned that crossing over increases the genetic diversity in a population because it reshuffles the genes of homologues. Some species have lost the ability to cross over and in other species, like humans, have lost the ability in certain chromosomes. What factors do you think could reduce levels of recombination between homologues? What would you hypothesize to be the control mechanism that would limit crossing over? 9. 10. Many animals show a phenomena known as “point restriction" where they have light fur color over the majority of their body even though their genotype should have dark fur color all over the body. Only in 'restricted regions of the body such as the extremities (ears, feet, nose) does the dark fur appear. Can your group hypothesis a mode of inheritance for these "point restrictions"? Gene turn on when it get cold ( changing temperature) ]

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Ans 7)

There is a mystery surrounding when it comes to comparing the chromosome number between humans and apes. The autosomes in humans are 23 pairs and in great apes it is 24 pairs. It is true that with gradual evolutionary there is one pair of chromosomes in humans that has been deleted. It seems like we have lost a pair of chromosome after human lineage was formed but many hypothesis states that wrong.

One of the hypothesis states that the chromosome has not been lost but the reduction might be a result of fusion of chromosomes. The chromosomes fuse every now and then and as the fusion of eggs and sperm occur, the pair of chromosome folds over each other. So this hypothesis is likely to be true that after the folding over each other, the chromosomes might have failed to separate and with gradual evolution, humans might have lost a chromosome as a result of fusion.

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