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## How many possible combinations of genotypes can there be?

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.

## How many possible chromosome combinations are there in a sperm?

A sperm cell contains 23 chromosomes with two possibilities for each chromosome. The possible number of sperm cells based on different chromosome combinations is (2)23 = **8,388,608**.

## How do you determine the number of different genotypes?

The number of different genotypes is **3 ^{n} where n = number of genes**. For simple dominant–recessive relations, the number of different phenotypes is 2

^{n}, where n = number of genes.

## Can AA and SS marry?

AC is rare whereas AS and AC are abnormal. Compatible genotypes for marriage are: AA marries an AA. … 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 different phenotypes are possible?

There are three common alleles in the ABO system. These alleles segregate and assort into six genotypes, as shown in Table 1. As Table 1 indicates, only **four phenotypes** result from the six possible ABO genotypes.

## How many different sperms are there?

Sperm cells come in **two types**, “female” and “male”. Sperm cells that give rise to female (XX) offspring after fertilization differ in that they carry an X-chromosome, while sperm cells that give rise to male (XY) offspring carry a Y-chromosome.