Inheritance of fruit color in summer squash provides an example of the phenomenon of epistasis. Yellow fruit is produced by a cross involving the homozygous recessive expression of the W gene (ww) and either the homozygous dominant (YY) or heterozygous (Y y) form of the Y gene. The wwyy outcome is green fruit.
Example of dominant epistasis is the colour of the summer squash fruit. So, option B is the correct answer. Note: The phenotype is not necessarily dependent on the genotype of an organism.
The phenotype of an individual depends on the expression of the genotype. Expressivity is the intensity with which a particular genotype is expressed. Analyzing Fruit Color in Squash: In summer squash, the fruit color can be white, yellow, or green.
The white fruit color is produced by a dominant epistatic allele (W). In summer squash or Cucurhita pepo, there are three types of fruit colour' yellow, green and white. White colour is dominant over other colours while yellow is dominant over green.
White fruit color in summer squash is dependent on dominant allele W and colored fruit on recessive allele w. In the presence of ww and a dominant gene G, the color of the fruit is yellow. An example of dominant epistasis is found for fruit colour in summer squash.
There are three types of fruit colours in this cucumber, viz., white, yellow and green. Fruit color in summer squash is an example of epistasis, where genotypes W produce white fruit, wwyy produce green fruit, and ww, YY, or Yy produce yellow fruit. For example, fruit colour of Summer squash (Cucurbita pepo) is governed by a gene which produces yellow colour in dominant state (Y-) and green colour in recessive state (yy).
Example with yellow, black, and chocolate labs. Dominant Epistasis Dominant epistasis happens when the presence of a dominant allele of one gene masks the expression of the second gene, leading to a 12:3:1 ratio. Illustrated with squash fruit color where white fruit is dominant over other colors.
Gene Expression and Penetrance. The summer squash fruit colour can be white, yellow or green. White fruits producing epistatic alleles are 'W'.
Y is for yellow fruits which is dominant to y which is for green fruits. White masks the effect of yellow or green. Hybrid ratio obtained is 12 white: 3 yellow: 1 green.