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A group of tightly linked genes that are involved in similar molecular pathway are called supergenes. For the pleasure to formulate a slight opposition to @shigeta's answer, I will give some examples of supergenes in eukaryotes. In Primula, heterostyly is controlled by a supergene. In Papilio memno, mimicry is controlled by a supergene. In some species of ...


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The reason is that X-inactivation is not complete (Carrell & Willard, 2005; Ahn & Lee, 2008), and as many as 15-25% of X-linked genes escape silencing (Carrell & Willard, 2005; Cheng et al, 2005). This means that some genes on the Barr body are expressed in XX-females, although often at lower levels compared to the active X-chromosome, and this ...


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TL;DR: Ubiquitin. Occasional occurrence of paternal inheritance of mtDNA has been suggested in mammals including humans. Clearly, spermatozoa have mitochondria; they make the energy needed for motility. Paternal mitochondrial DNA (mtDNA) does enter oocytes. It is a persisting fallacy that only maternal mtDNA is present in humans because only oocyte ...


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...would then be his offspring at risk? Why? No. Generally speaking, fathers do not pass on their mtDNA (Mitochondrial DNA). Why? Because the mitochondria present in oocytes (egg cell) is the mother's, as every oocyte directly inherits the mother's mitochondria when they are made in the reproductive organs. The mitochondria that the sperm from the ...


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Very interesting question! And I don't think either that the linked Wikipedia article answers the question. Unfortunately I do not know the answer for sure, but I might have some relevant information to add. So, from my studies I know that Barr-bodies are not totally inactive, they, in fact, do have some very limited transcriptional activity. It might be ...


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That's an interesting model, because mosquitoes are vectors for serious illnesses, so are pretty well studied. One team of scientists are working on genetically altering mosquitoes in Africa to make them unable to transmit the parasite that causes malaria. As the mosquitoes breed, it spreads through the population. In an interview, the lead researcher ...


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Note: This is based on literature searches I've done a while ago out of general curiosity. I'm in no way an expert on human reproduction. First, I'm not sure if you are asking about evolutionary reasons or the developmental causes for for a difference in sex ratio. Here, I will focus on the developmental causes. There is much evidence for a male bias in ...


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There is an article in the Journal of Popular Science from 1885. However, I do know there is at least one more recent article floating around some where since I read it. At the moment, I can't find it but will update if or when I do. The article goes on to state that during times of scarcity the number of male births outweighs the number of females whereas ...



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