28 is boards

Asked by  | 27th Mar, 2009, 12:14: PM

Expert Answer:

 

In sexual reproduction, Crossing-over and Independent assortment promote variation. During prophase of meiosis, crossing-over results in chromosomes that have some genes from one parent and some genes from the other parent. 

Individuals contain two sets of each chromosome but gametes contain only one set.  For each homologous pair of chromosomes, one chromosome will be randomly selected for each gamete formed (independent assortment).

The variation produced during meiosis is inherited, which means that evolution can take place as a result of the natural selection of certain variants to suit a changing environment. The way that meiosis gives rise to variation is by recombining genes from chromosomes in new ways. When the number of chromosomes is halved, there is some randomness in the way parts of chromosomes are selected to go into the gametes.

Answered by  | 27th Mar, 2009, 01:04: PM

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