Women with the 47 XXX karyotype are often fertile If a 47 XX

Women with the 47, XXX karyotype are often fertile. If a 47, XXX woman has children with a normal 46, XY man, what are the possible sex chromosome genotypes of their progeny? For each, specify whether the individual will be male or female, and whether they are likely to be sterile or fertile. In humans and other mammals, individuals with an X0 sex chromosome genotype (where 0 indicates a missing sex chromosome) are__whereas individuals with an XXY sex chromosome genotype are__. What sex would these individuals be in Drosophila? a. If you knocked out the gene Xist in a cell line derived from a female mouse, would you expect to detect higher, lower or unchanged expression ofX-linked genes? Explain! b. What if you instead knocked out the gene Sxl in a cell line derived from a female Drosophila? Would you expect higher, lower or unchanged expression of X-linked genes? Explain!

Solution

6                                                           XXX      x          XY

                  Gametes            X         XX             x          X   Y

                 Progenies                   XX XY            XXX    XXY

          XX Normal female, XY Normal Male, XXX Female with triple X syndrome and XXY Male with          

          Klienfelters syndrome.

           Out of this only XXY individuals will be sterile, rest all will be fertile.

7 In humans and other mammals, individuals with an XO sex chromosome genotype are females with Turners Syndrome whereas an individual with an XXY sex chromosome genotype are males with Klienfelters Syndrome.

In Drosophila XO individuals are metamales (low viability individuals) and individuals with genotype XXY will be normal females.