# What fraction of the offspring is heterozygous?

Contents

There are 4 out of 16 possible combinations of gametes from an SsYy x SsYy cross with the genotype of SsYy. We would therefore predict that 4/16 (or 1/4) of the offspring of the cross would be heterozygous for both traits.

## What fraction of offspring will be heterozygotes?

On average, half of the children will be heterozygous (Aa) and, therefore, carriers. The remaining half will inherit 2 recessive alleles (aa) and develop the disease.

## What is the offspring of heterozygous?

In other cases, each parent provides a different allele of a given gene, and the offspring is referred to as heterozygous (“hetero” meaning “different”) for that allele. Alleles produce phenotypes (or physical versions of a trait) that are either dominant or recessive.

## What fraction of the offspring is homozygous?

The genotypes of the offsprings by random fusion of the gametes produced by two plants can be calculated by checker board method. Thus 1/4th or 25% fraction of the population approximately will be homozygous for both the traits.

## When 2 heterozygous parents are crossed in a dihybrid cross what fraction of offspring will be homozygous recessive?

In a dihybrid cross, AaBb x AaBb, what fraction of the offspring will be homozygous for both recessive traits? 1/4 of the gametes of each parent will be ab. The fraction of the offspring homozygous for both recessive traits will be 1/4 times 1/4, or 1/16.

## Which of the following is a heterozygous genotype?

An organism with one dominant allele and one recessive allele is said to have a heterozygous genotype. In our example, this genotype is written Bb. Finally, the genotype of an organism with two recessive alleles is called homozygous recessive. In the eye color example, this genotype is written bb.

## How do you find the genotypes of parents given offspring?

To construct a Punnett square, the genotypes of both parents must be known. One parent’s alleles are listed across the top of the table, and the other parent’s alleles are listed down the left hand side. The resulting offspring genotypes are produced at the intersection of the parent’s alleles.

## What happens when cross 2 heterozygous?

Tutorial. The expected genotype ratio when two heterozygotes are crossed is 1 (homozygous dominant) : 2 (heterozygous) : 1 (homozygous recessive). … The heterozygotes have a phenotype distinct from normal cats.

## What fraction of the offspring will be homozygous recessive for both traits?

The correct answer is 1/16. A dihybrid cross results in a phenotypic ratio of 9:3:3:1. The 1 in the ratio is indicative of the double recessive phenotype, with a homozygous recessive genotype for both traits. Thus, only 1/16 of the offspring will display both recessive phenotypes.

IT IS SURPRISING:  Question: Can someone with Down syndrome drive?

## What fraction of the offspring is AABB?

There is only one possible offspring with the aabb phenotype of 16 total, so the fraction with this genotype will be 116 .

## When heterozygous plants and homozygous dominant plants have the same phenotype?

Because homozygous dominant and heterozygous individuals are phenotypically identical, the observed traits in the F2 offspring will exhibit a ratio of three dominant to one recessive.

## What fraction of the offspring of a dihybrid cross have the recessive phenotype for both traits?

The correct answer is 1/16. A dihybrid cross results in a phenotypic ratio of 9:3:3:1. The 1 in the ratio is indicative of the double recessive phenotype, with a homozygous recessive genotype for both traits. Thus, only 1/16 of the offspring will display both recessive phenotypes.

## What is the ratio of one pair of contrasting characters in F2 of a dihybrid cross?

The ratio of the contrasting characters in F2 as 1 : 2 : 1. Explanation: The ratio of the genotypes of the second filial generation comes as 1 : 2 : 1. Dihybrid cross is the cross which is made after the crossing for two generations.

## What are the possible genotypes for the genetic cross between SsYy and SsYy?

Answer and Explanation: The possible genotypes for the combination of SSYy and SsYy are those where the offspring inherits either allele at each gene from either parent: The SSYy parent has gametes for SY and Sy. The SsYy has gametes for SY, Sy, sY, and sy.