Why does an individual have the number of alleles for a trait they do? In other words, where do the alleles come from

- An individual has two set of alleles for each trait because humans are diploid (two set of chromosomes).

Explanation:

Humans are DIPLOID in nature, meaning that they have two sets of each chromosome. Chromosomes contains genes, which come in different forms or versions called ALLELES. Since there are a pair of each chromosome, then there are two genes per chromosome. Hence, two possible forms of genes (alleles) can exist for each gene. That is, every gene will have two copies.

The alleles of each gene on a chromosome comes from each of the parents of an individual. For example, a human contains 23 pairs of chromosomes. Each pair of chromosome comes from the father and mother.

Explanation:

It is important to note that alleles can be dominant, recessive, or codominant to each other, leading to variations we see in different organisms and traits. For example, how we can differentiate people by their eye color, blood group, hair color, all show that an allele is a specific form of a gene.

An individual has the number of alleles for a trait they do because each cell needs only certain genes to be active or activated in order to function genetically and since gene influence the way cells functions, so for each trait, there are two alleles per gene making an individual having two identical alleles of a particular gene or genes when the two alleles are the same. While having two different alleles of a particular gene or genes, when the two alleles are different. This is so important as the alleles affect the expression (phenotype) of a particular trait.

explanation:

the fossil record extends back to a dog-like ancestor some 55 million years ago, which gave rise to the first horse-like species 55 to 42 million years ago in the genus eohippus.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."