College of Cat Genetics: Part II
by Patricia Turner
Answer: The chromosome complement of the two types of gamete
produced by the male cat are (a) 36 autosomes plus two X chromosomes, and
(b) 36 autosomes, one X chromosome and one Y chromosome. (a) gametes
will be female and (b) gametes will be male.
Answer: Genetic differences arise during meiosis rather
than from mitosis because mitosis is the normal type of cell division in
which the cells divide in a manner resulting in all the daughter cells
retaining the full complement of 38 chromosomes. But in the cell
division that occurs just before the gametes are formed (meiosis) each
daughter cell has only 19 chromosomes. It is only at fertilization,
when the daughter cells from each partner unite, that the full complement
of 38 is regained. Clearly the fertilized cells will have some chromosomes
from each parent and will differ from those produced by each parent during
mitosis. Mitosis results in daughter cells with the same chromosome
complement whereas meisosis results in daughter cells with half the chromosome
Answer: No, a mating between an Oregon Rex queen and either
a Cornish or a Devon Rex queen will not produce any rex kittens.
They will all have normal hair. The non-rex kittens will be carriers
for both Rex varieties as the three varieties of rex are
non-allelic to each other.
Answer: The Tabby (or Lynx) Point kitten is heterozygous for agouti. The Seal Point kitten will never produce Tabby (or Lynx) Points if mated to Seal Points.