Patterns of inheritance

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Question 1
Medium

The fruit color in summer squash (Cucurbita pepo) is determined by two genes, W/wW/wW/w and Y/yY/yY/y.

  • WWW is a dominant allele that inhibits pigment deposition, resulting in white fruit.
  • The recessive allele, www, allows pigment deposition so the fruit develops color.
  • YYY is a dominant allele that codes for the production of a yellow pigment.
  • Summer squash plants that are homozygous for the recessive allele, yyy, produce green fruit (in the absence of dominant inhibiting alleles).

A white squash plant was cross-pollinated with a yellow squash plant. All offspring had the genotype WwYyWwYyWwYy.

a.

Identify the following:

  • The genotype of the white squash parent plant
  • The genotype of the yellow squash parent plant
  • The phenotype of the offspring
[3]
b.

State the type of gene interaction shown by the genes W/wW/wW/w and Y/yY/yY/y.

[1]
c.

Suggest how the dominant allele WWW inhibits the expression of allele YYY.

[2]

Patterns of inheritance Questions

  1. A Level
  2. /Biology
  3. /Patterns of inheritance