In this chapter, we have focused on sex differentiation, sex chromosomes, and genetic mechanisms involved in sex determination. At the same time, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter, you should answer the following fundamental questions? How do we know that in humans the X chromosomes play no role in human sex determination, while the Y chromosome causes maleness and its absence causes femaleness?

Video transcript

Hi everyone welcome back. Let's look at our next problem. It says the X. X. Y. Disorder, also known as Klinefelter syndrome, affects men. Whereas the X. O. Disorder, also known as Turner's affects women. Based on the aforementioned data, we may draw the conclusion that blank chromosomes determine sex in humans. So other question tells us when the person's genotype is X. X. Y. You have a male phenotype and when the genotype is X. O. You have a female phenotype. So this is despite the fact that in the X xy genotype of Klinefelter syndrome, you have two X chromosomes. Whereas in the Turner syndrome you have one X chromosome. The oh here means it's zero. It means there's no second sex chromosome, just a single X chromosome. So based on that, you can draw the conclusion that it's the Y chromosome that determines sex if the Y chromosome is present, you have a male phenotype. If the Y chromosome is absent, you have female phenotype regardless of the number of X chromosomes that are present. So we'll look at choice a the Y chromosome for answer here. And that is the result of a gene on the Y chromosome called the S. R. Y. Gene. And that gene codes for a specific protein. It makes a protein called the sex determining region Y protein. And this is involved in male typical sex development. So that would be the reason for that why chromosome being determinant of sex in humans. So our answer here again is choice A the Y chromosome see you in the next video