Genetics Answers

In peas, a gene for tall plants (T) is dominant over its allele for short plants (t). The gene for smooth peas (S) is dominant over its allele for wrinkled peas (s). The genes are not linked. Determine both phenotypic and genotypic ratios for the results of each of the following crosses:

3.2. homozygous tall wrinkled x short heterozygous smooth.                 [26 marks]

In peas, a gene for tall plants (T) is dominant over its allele for short plants (t). The gene for smooth peas (S) is dominant over its allele for wrinkled peas (s). The genes are not linked. Determine both phenotypic and genotypic ratios for the results of each of the following crosses:

3.1. heterozygous tall heterozygous smooth x heterozygous tall heterozygous smooth.                                                             

Draw a pedigree for at least three generations of a family where an X-linked dominant trait is being inherited. Include an affected male and an affected female in your pedigree as well as unaffected individuals. Write out the genotypes for an affected male, affected female, unaffected male, and unaffected female.

In some bacteriophages, DNA often appears in the form of a single helix. Which of the following forms represents this form of DNA? A) A-G-C-T B) A-G-U-C C) A-G-T-U

A housefly has six pairs of chromosomes. If two houseflies are crossed, how many possible types of fertilized eggs could result from the random lining up of the pairs?

In peas, a gene for tall plants (T) is dominant over its allele for short plants (t). The gene for smooth peas (S) is dominant over its allele for wrinkled peas (s). The genes are not linked. Determine both phenotypic and genotypic ratios for the results of each of the following crosses:

1.1 homozygous tall wrinkled x short heterozygous smooth.                  [26 marks]

1.2. short heterozygous smooth x heterozygous tall wrinkled.                 [26 marks]

1.3 heterozygous tall homozygous smooth x short wrinkled.                  [26 marks]

In peas, a gene for tall plants (T) is dominant over its allele for short plants (t). The gene for smooth peas (S) is dominant over its allele for wrinkled peas (s). The genes are not linked. Determine both phenotypic and genotypic ratios for the results of each of the following crosses:

3.1. heterozygous tall heterozygous smooth x heterozygous tall heterozygous smooth.                                                                                          [26 marks]

In a particular species of plant, tall is dominant to short, and orange petals are dominant to the recessive white colour. Use T and t to symbolize the alleles for height, and F and f to symbolize the alleles for flower colour. A homozygous tall white flower is crossed with a flower heterozygous for both traits.

1.1 List the genotypes of the parents.                                           

1.2 What are the F1 GENOTYPIC and PHENOTYPIC ratios?          [5 marks]

1.3 What are the F2 genotypic and phenotypic ratios?   

In a particular species of plant, tall is dominant to short, and orange petals are dominant to the recessive white colour. Use T and t to symbolize the alleles for height, and F and f to symbolize the alleles for flower colour. A homozygous tall white flower is crossed with a flower heterozygous for both traits.

1.1 List the genotypes of the parents.  

1.2 What are the F1 GENOTYPIC and PHENOTYPIC ratios?  

1.3 What are the F2 genotypic and phenotypic ratios?