Suppose louise wants to breed parakeets that are yellow with patterned feathers. however, when she bred several parakeets that were yellow with patterned feathers, she found that there were four different offspring phenotypes. based on the offspring data provided below, determine the number of genes and alleles that control these phenotypes.

The cross involves two gene having two alleles each.

Further Explanation:

Two phenotypes of parakeets was taken as the observation while breeding them. The phenotypes selected was:

As two traits has been selected so two genes would be involved for them and each gene has two alleles.

Four different offspring phenotype was observed after breeding. This could only be possible if the cross involved was a dihybrid cross.

The dihybrid cross involves  two genes encoding two different  traits. The dihybrid cross has the phenotypic ratio of 9:3:3:1. This ratio can be explained in the following manner:

1. 9 out of 16 has presence of atleast one allele in dominant form for both the genes. For example in this case it will be: Y_P_.

2. 3 out of 16 has presence of atleast one allele in dominant form for a gene and other gene will have recessive alleles. For example in this case it can be either Y_pp or yyP_.

3. 1 out of 16 has presence of both allele in recessive form of both the gene. For example in this case it will be yypp.

The phenotypic ratio can be calculated using the formula: .

Learn more:

1. Learn more about genetic code link

2. Learn more about RNA link

3. Learn more about DNA link

Answer Details:

Grade: College Biology

Subject: Biology

Chapter: Genetics

Keywords:  

Genotype, cross, gene, allele, dihybrid cross,  phenotypes, dominant form, recessive alleles,  phenotypic ratio.

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.