Question

Hi can someone please explain to me which answer is correct and why?

uoumed tu exunctiun because bloldiess is caused by a recessive gene. In trutn, the genetics of human hair color is considerably more complicated than the story postulates.345d But what if hair color really were that straightforward? If blondness were a simple recessive trait, would that mean flaxen hair is predestined to disappear? Q1.1. Do you think recessive traits automatically disappear from populations? Yes. Recessive traits tend to become less common every generation until they vanish altogether. No. Recessive traits tend toward a frequency of 25%. If they are more common than this, their frequency will fall, but if they are less common, their frequency will rise. O No. Recessive traits tend to remain at a constant frequency unless there something else is causing their frequency to change. No. Recessive traits tend to become more common every generation until they reach a frequency of 100%. Record Prediction To answer this question with confidence, we have to know what it means to call a trait recessive. And we have to understand how genes behave in populations. To do this, you'll conduct experiments using a simulation model. Your experimental subjects will be animals somewhat more amenable than humans to selective breeding: domestic swine.

Answer 1

The correct answer is "No. Recessive traits tend to remain at a constant frequency unless there is something else is causing their frequency to change.

Let us explain this by taking an example of short and tall people. Short are considered as recessive and tall are considered as dominant trait. They are controlled by the genotypes tt and TT or Tt respectively. In a population, let us assume that the frequency of tt is 5%, TT is 30% and Tt is 65%. Lets assume that within this population there was a cross between Tt and Tt. This leads to the following genotype TT, Tt, Tt, tt. The tt here is a recessive trait and if this undergoes another cross with Tt, then the frequency of tt raises drastically. For example this cross gives Tt, Tt, tt, tt. Earlier it was 25%. But after the second cross it became 50%. This happens most oftenly during consagious (marriages within relatives). Hence, although recessive trait frequency was very low initially, it tends to increase due to consagious marriage.