What specific observations (evidence) support the conclusions about sex determination in Drosophila and humans?

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Everyone. Let's look at the next problem. It says males only have one X chromosome, whereas females have two X, the O in XO denotes the lack of the second sex chromosome. Exofila is a blank whereas it, whereas it is a blank in humans. Well, to answer this question, we have to understand the difference in sex determination between Drosophila and humans. So in Dr Sophal, it is the ratio of X to A. So the ratio of X chromosomes to ooms that determines sex. So if that ratio is 1 to 1, you have a female, so the presence of two xes, when there are two of every other autosome determines a female, a ratio of one half to one equals male. So in this case, if the individual has a genotype of xo that will equal a male genotype. However, um without the Y chromosome, these males are infertile. So we have an infertile or sterile male resulting from opal with an xo genotype. So that will be in choice A and choice C. So we'll go ahead and eliminate choices B and D which say that the opal would be female in that case. So now let's think about the human situation and humans, it's the presence of a Y chromosome that determines sex, uh particularly the sry gene on that Y chromosome. So without the Y, so no Y chromosome, you have been a typical female with a Y chromosome, you have a male and that's regardless of how many X chromosomes there are. So in this case, Xo you only have one X but there is no Y chromosome. So in humans, that will lead to an individual who is phenotypic female. However, as with the exo Andros Sophal, um without the second X, that individual is infertile. So when we look at the answer, choices, we have the choice between um and choice. A Axo and humans being a fertile male or in choice C A sterile female. The correct answer is sterile female. We can eliminate choice a since the person will not be male and our correct answer is choice. C so exo droil is a sterile male whereas it, whereas it is a sterile female in humans. See you in the next video.

What specific observations (evidence) support the conclusions about sex determination in Drosophila and humans?

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Key Concepts

Chromosomal Basis of Sex Determination

Genetic Evidence from Mutant and Aneuploid Individuals

Experimental Crosses and Phenotypic Ratios