Does having a dominant allele mean that it will be found in greater frequency in the population?

Answer 1

No. For example, the six-finger allele is dominant over the five-finger allele in humans, yet you see almost nobody with six fingers, because it has such a low frequency. It all depends on the allele frequency in a given population.

Answer 2

If an allele is dominant, it is more likely to be passed on to the next generation. Genetics is complicated, but in a very simplistic manner, it can be explained this way:

Each person has 2 copies of each gene. One comes from the mother and one comes from the father. If the father is AA (autosomal dominant - the father contributes 2 copies of a dominant allele. Autosomal means these are not sex-linked genes) and the mother is AA (autosomal recessive - the mother contributes two copies of the recessive gene) all the subsequent children will be Aa (heterozygous - one copy of each). These is because the only possible combination to make when you cross the two is Aa. Let's call the father's allele A1 and A2 and the mother's alleles a1 and a2. If A1 and a1 are xcontributed to the offspring, the result is Aa. If A1 and a2, then Aa. If A2 and a1, then Aa. If A2 and a2, then Aa.

Let's try a more complicated version:

If the father were Aa and the mother were Aa, there would be a 25% chance of AA, 50% chance of Aa and 25% chance of AA. If we call the father's alleles A1 and a1 and the mothers A2 and a2, then:

A1 + A2 = AA

A1 + a2 = Aa

a1 + A2 = Aa

a1 + a2 = AA

As far as what determines dominance, that is a far more complicated question.

Answer 3

It depends on the trait. If the dominant genotype is selected for more often than the recessive genotype, then the dominant allele will become more common in the gene pool. If the recessive genotype is selected for more often than the dominant genotype, the recessive allele will become more common than the dominant allele in the gene pool. For example, in humans, having five digits on hands and feet is recessive, and six digits is dominant. Most people have five digits because the recessive allele for numbers of digits is much more common in the human gene pool than the dominant allele.

Answer 4

Not necessarily. It depends on the frequencies of the dominant and recessive alleles in the population. For example, having six digits on the hands is a dominant trait. But almost nobody has six digits because the recessive allele is by far the most abundant in the population.

Answer 5

Yes, it is. If no particular survival or reproductive advantage is granted by the dominant allele, then it won't be preferred by natural selection and may be rare.