According to the chromosomes theory of sex determination, the male and female individuals would differ in their chromosome constitution. There may be two types of chromosomes present in such individuals: (1) autosomes, and (2) sex chromosomes. In a diploid individual, there are 2n-2 autosomes and two sex chromosomes. The experiments of C.B. Bridges on the nondisjunction of X-chromosomes proved that a diploid set of autosomes with two X-chromosomes will always give rise to a female individual irrespective of whether the two X-chromosomes came from the same parent.The above example illustrate that the Y -chromosome does not carry any sex determining factor. The presence of one or two X-chromosomes is more important than the presence or absence of Y-chromosomes.
Posted by orchid101
on July 18, 2013 at 8:56 AM (Answer #1)