List as many human traits as you can that are likely to ...

Question

List as many human traits as you can that are likely to be under the control of a polygenic mode of inheritance.

Accepted Answer

Hi everyone, welcome back. Let's look at our next question. Skin color in humans shows a lot of variation. This is an example of which type of inheritance. So as our question reminds us and we can recall skin color in humans uh shows a wide amount of variation. You don't have discrete and distinct shades of skin color. You have this bell shaped curve distribution of all different shades of skin color. And this is very characteristic of inheritance controlled by multiple genes that have an additive effect. So skin color has multiple genes and they are interacting to influence a single phenotype skin color in an additive manner. So each of these genes has different alleles that the individual kind of inherited from a parent. And then you add together the effect of each of those different alleles inherited to create that final phenotype so that when you have multiple genes interacting for a single phenotype, that's going to be choice. The palla genic inheritance. Again, we've got the prefix poly meaning many many genes. So let's look at our other answer choices to understand why they're not correct. The trickiest one I think is choice a co dominance. Because co dominance can can produce phenotype that are sort of intermediate. You can imagine uh the flower color where you have a gene and a little for red flower color and white flower color and their co dominant. So if an individual flower has copies of each, the flower will be pink. So you have this intermediate color. But it's not this gradient that we see in human skin color. You just have red, pink white. You have three discrete values and in co dominance it's a single gene. But multiple alley ALs that don't mask each other. So when you have of course recessive and dominant inheritance, the dominant allele masks the effect of the recessive allele in co dominance. Those alleles combined rather than masking each other. But there are multiple alleles of a single gene. You don't have different genes working together. So that's why this is not an example of co dominance. But it can be a little tricky to keep the two straight. But if you just keep focused on apologetic means multiple genes, co dominant, multiple allies of a single gene. So that's why A is not correct. Choice B is multiple alleles and same reason as co dominance. Not correct. When you're just talking about multiple alleles, that can mean just a single gene with multiple alleles controlling the phenotype. Whereas skin color, apologetic inheritance controlled by multiple genes. And then choice C. Play a trophy almost the opposite apologetic. You have a single gene with multiple effects. So an example of this would be in various genetic disorders where you might have a mutation in the gene for a single protein. But because that protein has so many functions in the body, you would have multiple fanatic effects of that disease. You would see multiple uh issues in maybe anatomy or organ function or other effects like that all caused by a mutation to a single gene. So an effect of a single gene on multiple systems and that's play a trophy, but not a correct answer, Since it's sort of the opposite of what we're talking about. So again, skin color in humans, example of which type of inheritance? Choice D. Apologetic inheritance you in the next video.

List as many human traits as you can that are likely to be under the control of a polygenic mode of inheritance.

Key Concepts

Polygenic Inheritance

Quantitative Traits

Environmental Influence on Traits

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