Topic 1 - Variation: Genetic Diagrams

Question 1

A tall pea plant with two dominant ‘T’ alleles and a dwarf pea plant with two recessive ‘t’ alleles are crossed to produce a pea plant with the genotype Tt. What will the new plant’s phenotype be?

Answer 1

The plant will be tall, as the tall allele (T) is dominant over the recessive dwarf allele (t). The plant will only be dwarf if its combination of alleles is tt.

Question 2

What will the offspring’s possible genotypes and phenotypes be, if B represents blue eyes, and b represents green eyes and the mother and Father’s genotypes are both Bb.

Answer 2

BB - blue eyes, Bb - blue eyes,

Bb - blue eyes, bb - green eyes.

Question 3

What do the terms genotype and phenotype mean?

Answer 3

Genotype means what combination of alleles you have. Phenotype means the characteristic you display as a result of your genotype.

Question 4

A pink-haired hamster with two dominant ‘H’ alleles is crossed with a yellow-haired hamster that has two recessive ‘h’ alleles. If the resulting hamster has the genotype Hh, what will its phenotype be? Explain why.

Answer 4

The hamster will be pink- haired, as the pink hair allele (H) is dominant over the recessive yellow hair allele (h). The hamster will only have yellow hair if its combination of alleles is hh.