Mangile's Pigeon Pages

Sex Chromosome

In female pigeons it was discovered that all chromosomes were paired except one.  This very fact -  a single (not paired) chromosome - gives rise to a female. (Figure 1.)

When the same chromosome is paired the offspring results in a male.  This chromosome has been labeled as the "sex chromosome".  (Figure 2.)

Because this chromosome is linked to the sex of the individual (single produces a female; paired produces a male) its genes are called "sex-linked genes".   The sex of some individuals can often be determined by the expression of its sex-linked gene(s).  (Keep in mind that the characteristics of an individual are the end result of the action of a gene, either acting alone or in combination with other genes.)


Figure 1.

Female with un-paired sex chromosome.  Showing a single chromosome which gives rise to a female; and the eventually discarded polar body.


Figure 2.

Male with paired sex chromosomes.  Showing the same chromosome in Figure_1; but paired;  therefore, giving rise to a male offspring.


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