A quantitative trait                   . a. may be one that is strongly influenced by the environment; b. varies continuously in a population; c. may be influenced by many genes; d. is not either off or on; e. all of the above

Video transcript

Hi everyone. Here's our next problem. A quantitative trait is controlled by numerous genes, quantitative traits are also known as blank traits. We have choices of recessive, dominant apologetic or mono genic. Well we're given a clue right here in our problem. It says a quantitative trait is controlled by numerous genes. When we look at our last two choices CNG we have apologetic and mono genic. Um These are obviously frequent prefixes in the biology world poly meaning many mono meaning one. And we have numerous genes. So polly genic is this answer. This problem points us right to the answer apologetic and that mon a genic is incorrect but we want to be through here and kind of walk through why quantitative and apologetic can refer to the same thing. So since palla genic traits results are traits where multiple genes contribute to a phenotype. Um the apologetic traits don't have the same recessive dominant opposition that um unhygienic trait does. So in a mono genetic trait let's look at um like tall versus dwarf plant where you've just got, it can be either or two discrete values, it can be tall or it can be short and you've got a dominant gene and a recessive gene. And if you have a hetero ziggy you don't get a medium height plant. In this situation you get a tall plant because the recessive gene is masked by the dominant gene but that is not the case with these quantitative traits. Instead, each gene contributes. So say in the human height contributes something towards the final fanatic value. And so at the end result you have a wide range phenotype sis in a bell shaped distribution rather than those discrete um Mandelli in ratios that you see with mono genic inheritance. So quantitative we can think of as you know, a range of values, a range of numbers versus the discrete values you see in mono genic inheritance. So we don't see straight ideas of a recessive or be dominant genes because each of the genes in that trade are contributing towards the final phenotype. So again, quantitative traits also known as choice. See apologetic traits. See you in the next video.