Re: CP evolution

Jan Schlauer (
Wed, 21 Jun 1995 11:16:33 +0100


>Jan, you
>mentioned that there is no selection of genotype, but I remember studying
>that this does exist. Like when a genotype is hybrid between similar
>taxons, the chromosomes may not separate well in meiosis, resulting in
>inviable gametes with different numbers of chromosomes. Depending on the
>situation, 1/2, or 1/3, or 2/3, etc., of the gametes will be inviable. I
>think there were a few other similar cases where certain genotypes could
>be more advantageous.

As almost always with "strict" rules (e.g. "there is no selection of
genotype"), they do not completely fit experience without further
explanation. At least the caryotype (composition of the genome of specific
chromosomes and chromosome numbers) is a phenotype even if the chromosomes
themselves are carrying the genotype. Still a (simplistic) model of
evolution can be applied: (1.)mutations leading to (2.)genotypic variation,
leading to (3.)phenotypic variation, leading to (4.)selection of "favoured"
phenotypes starting again with (1.) (with 2. & 3. being very close to each
other in our case).

Kind regards