In the past the IOC has employed two genetic sexdeterminatio

In the past, the IOC has employed two genetic sex-determination tests. The Barr body test screens for the presence of two X chromosomes. In XX somatic cells, one copy of the X chromosome condenses into a largely inactive structure called a Barr body, which can be seen using a light microscope, In more recent years, a polymerase chain reaction-based screen has been used to amplify the DNA sequence of the SRY gene, which is found only on the Ychromosome. Based on their karyotypes, what would be the outcome of these two tests for each of the four individuals? Drag the labels to indicate the presence or absence of a Barr body and the SRY gene sequence. (For help interpreting the karyotypes, see Hint 1) Barr body? SRY sequence? Normal female (control) Normal male (control) presen absen Athlete 1 Athlete 2 Submit Hints My Answers Give Up Review Part

Solution

A normal female has two copies of the X chromosome and no Y chromosomes, so one barr body will be present for the extra X chromosome and no SRY gene due to the absence of Y chromosome.

A normal male have no barr bodies as there is only one copy of X chromosome and SRY sequence will be present as Y chromosome is present.

In case of the athletes, in both cases there is one X and one Y chromosome, so no barr bodies. And due to the presence of Y chromosomes, SRY sequences will be present in both.