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Self Assessment Answer #
1
by Dr Jamie Love |
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Self Assessment Answer #
1
by Dr Jamie Love |
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During metaphase I the homologous pairs of chromosome are paired up as tetrads along the metaphase plate.
At anaphase I they separate independently of each other so either
member of each pair can end up going to either pole. That can
generate many different combinations of chromosomes at each pole
and thus produce many different combinations of gametes.
Each gamete will have the proper number of chromosomes and one
of each type (#1, #2, #3, etc.).
It is random whether each will be maternal or paternal.
During prophase I the homologs, which are difficult to see at
this stage, exchange chromatid pieces amongst themselves. Each
of these exchanges is a crossing over event and allows the
sequence of genetic materials along a chromosome to be exchanged
between the M and P chromosomes. This is kind of like the randomness
that is produced at anaphase I but here it is occurring within
each pair of homologous chromosomes.
By late prophase we can see that these areas of exchange as chiasmata.
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