Thank you! You're all awesome at answering my questions...
XYY humans are fertile males. XXX humans are fertile females. What do these observations reveal about the mechanisms of sex determination and dosage compensation?
So I understand the whole "inactive" allele, for the most part. But I don't really understand exactly how to answer this specific question. Could someone clarify this concept for me? Or a link that clarifies it? I'm having no luck!
Sorry- I'm more math-minded. Genetics is giving me a tough time! I need some more explanation than an online class, I'm learning!
Ok... This is what I ended up with for an answer. For the sake of contributing something to the forum. I hope this makes sense, and I would like a second eye on it.... I think it fully answers the question.
XYY humans are fertile males. XXX humans are fertile females. What do these observations reveal about the mechanisms of sex determination and dosage compensation?
Answer:
The two process’ of sex determination and dosage compensation are likely related.
Generally, both alleles are expressed because mammals are diploid and produce both copies of every gene on their autosomes. However, sex determination is different. Because of the “inactive” gene, females produce two doses of transcripts for every one dose produced by males. This imbalance is corrected by dosage compensation. One of the two x chromosomes is randomly inactivated early in development. A barr body is the inactivated chromosome. This x chromosome inactivation is an example of epigenetic inheritance.
Basically, the existence of this type of epigenetic phenomenon shows that eukaryotic gene expression can be silenced, all without changing the DNA sequence of the gene.
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