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1

I don't think this is a complete answer, but I know that historically hair, like horse tail has been used as a part of armor, because it is flexible and difficult to cut through (see dragoon helmet picture). Protection could be one of the primary purposes of facial hair in human males, who are more likely to experience aggression or be hunters.


1

Human cells are irradiated with X rays (to fragment the DNA) and then fused with rodent cells. This is useful for mapping because closely linked markers are more likely to appear in the same hybrid: there is a lower probability of radiation induced breakage between the markers because they are close together.


1

Could not fit in a comment.... Northern Africans and Indonesians have pretty much the same skin color (to my first impression). Sub-Saharan African (that you don't talk about) are darker. And Northern Africa in not an equatorial region (not more than Los Angeles) as it is right under the tropic of cancer. Also I am a little confused about who you call "we" ...


3

You have made an incorrect assumption-- that all the genes on both chromosomes necessarily remain intact. It's possible that they do, and the the translocation is harmless. But the transition point could be within a gene. This would usually lead to that copy of the gene becoming inactive, which can cause diseases just like any other loss-of-function ...


3

In the Down syndrom typically, the translocation does not induce (usually; see later) any disease. We call someone carrying the translocation a "balanced carrier". The problem arises after, at the moment of segregation. When balanced carriers reproduce Consider someone who has a translocation as you showed. You showed only one chromosome of each types ...


4

Short answer Yes, the high frequency of polydactyly in the Amish is caused by inbreeding. Background The polydactyly in the Amish is just one of the symptoms of Ellis-van Creveld (EvC) syndrome. EvC syndrome is an autosomal recessive disorder, involving polydactyly of the hands (see figure), short stature with shortening especially of the forearms and lower ...


6

Short answer Yes, you pretty much nailed it. Inbreeding of (and from) an isolated population. Long answer According to wikipedia > polydactyly, there are 39 known polmorphic sites underlying variance in polydactyly. It is therefore not a trait with a simple mode of inheritance. There are two important (somehow related) concepts to understand to explain ...


1

Yes, people can definitely grow taller than their parents. Height is a polygenic quantitative trait (so affected by many genes), that is also strongly affected by environmental factors. You are also forgetting that there is a sex difference in height (~14 cm, Wright & Cheetham, 1999), so the height of the mother does for instance not set an absolute cap ...


0

It's been possible for a long time now. Take a look at this article related to trials with retroviral vectors used for gene therapy trials. A single child developed leukemia, and following that trials across the world were suspended. The article although notes that many countries decided to proceed with trials, since as they say "for the greater good". But ...



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