Question:
Does an organism's diploid chromosome number confer any
advantages- evolutionary or otherwise? For example a goldfish has a
diploid # of 188 does that make it more advanced than corn whose # is 20.
Replies:
Corin,
The obvious advantage is in gene expression in the event of genetic damage
or mutation. Where only one of the chromosomes is necessary for expression,
the presence of two can offer a 'backup' in the event the other does not
function properly or is damaged. Note that this however does not always
occur. With more genetic research we are finding that much of disease is
the result of genetic damage which is passed along to offspring and cannot
be 'undone' by genetic recombination with genetic material from the other
parent.
Regarding evolution, you may note that having diploid chromosomes, and
potentially more genetic variety, offers a great potential for survival in
the event chromosome option "A" is not well suited to the changing
environment of an area. If the presence of a "B" option is available, it
might be the expression which can tide the organism over a period when the
environment does not favor other genetic expression. Without diploid
chromosome numbers in this case, all of a genetic strain could die out and
take other number gene variability with it.
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