How many possible genotype combinations are there for any particular trait?

How many possible genotypes for a trait are there?

Genotype is also used to refer to the pair of alleles present at a single locus. With alleles ‘A’ and ‘a’ there are three possible genotypes AA, Aa and aa. With three alleles 1, 2, 3 there are six possible genotypes: 11, 12, 13, 22, 23, 33. First we must appreciate that genes do not act in isolation.

Can there be 4 genotypes?

Things get slightly more complex when considering two genes. For instance, a wild-type fly (with red eyes and a yellow body) has one of four possible genotypes: EEBB, EEBb, EeBB, and EeBb.

How many possible genotypes will make a recessive trait?

For an organism to demonstrate the recessive phenotype there is only one possible genotype that can be attributed to them. For example brown eyes (B) is dominant over blue eyes (b). If an organism has blue eyes, the only possible genotypic combination is (bb), as there cannot be any presence of the dominant gene.

How many genotypes are possible with 6 alleles?

Consider the case, though, of a locus with 6 alleles. It has 21 possible genotypes — 6 kinds of homozygotes and 15 kinds of heterozygotes. Writing it out, 6 + 5 + 4 + 3 + 2 + 1 = 21 = [6*(6+1)]/2 — this is the formula for combinations of six things taken two at a time, order unimportant — [n(n+1)] / 2.

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What is genotype AA?

The term “homozygous” is used to describe the pairs “AA” and “aa” because the alleles in the pair are the same, i.e. both dominant or both recessive. In contrast, the term “heterozygous” is used to describe the allelic pair, “Aa”.

Can As marry as?

However, AS and AS should not marry because there is every chance of having a child with Sickle Cell Disease, while AS and SS shouldn’t think of marrying. And definitely, SS and SS must not marry since there’s absolutely no chance of escaping having a child with the sickle cell disease.

How many genotypes are possible with 8 alleles?

Therefore, 8 alleles of a gene can have 36 possible genotypes in the population.

What is the genotype of the male female?

Most people have either two X chromosomes (genotypic female) or an X and a Y chromosome (genotypic male). Phenotypic sex refers to an individual’s sex as determined by their internal and external genitalia, expression of secondary sex characteristics, and behavior.

How many possible genotypes and phenotypes are there for a single gene trait that shows dominance?

As you know, if the allelic interactions known for a particular gene the genotype can be used to predict the phenotype. With one gene controlling a trait we have three possible genotypes, AA, Aa and aa and depending on the allelic interactions (dominance or incomplete dominance) we can have two or three phenotypes.

What are the 3 types of genotypes?

There are three types of genotypes: homozygous dominant, homozygous recessive, and hetrozygous.

What is the only genotype that can produce a recessive phenotype?

Only individuals with an aa genotype will express a recessive trait; therefore, offspring must receive one recessive allele from each parent to exhibit a recessive trait. One example of a recessive inherited trait is a smooth chin, as opposed to a dominant cleft chin.

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Does phenotype always express genotype?

The sum of an organism’s observable characteristics is their phenotype. A key difference between phenotype and genotype is that, whilst genotype is inherited from an organism’s parents, the phenotype is not. Whilst a phenotype is influenced the genotype, genotype does not equal phenotype.