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Biology - Crossing Over

Crossing over

Alleles [1] are alternative forms of genes [2] that occupy the same locus
[3] (location or position) on a pair of homologous [4] chromosomes. For
example, the gene for coat colour in guinea pigs has two alleles, one for
black hair and one for white hair. Crossing over resulting from
non-disjunction [5] (non-separation) of chromosomes at a chiasma [6] means
there is an exchange of alleles between paired chromosomes. New
combinations in the chromosomes of gametes [7] can occur because chromatids
will be of mixed paternal and maternal origin. In the following diagrams
upper case represents paternal chromosome, lower case represents maternal
chromosome.

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Links:
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[1] http://alison.com/#
[2] http://alison.com/#
[3] http://alison.com/#
[4] http://alison.com/#
[5] http://alison.com/#
[6] http://alison.com/#
[7] http://alison.com/#