Wildtype harebells have blue flowers. Two mutant strains of harebells have recessive, white flowers. First, describe in detail an experiment to test whether the mutations in these two strains of harebells affect the same gene. Second, describe in detail an experiment to determine how the two genes interact if the mutations happen to affect different genes. Underline the following terms in your answer: complementation, dihybrid cross, haplosufficient, and phenotype ratio.

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Sixta KovacekLv2

30 Jul 2018

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Related questions

Wild harebells have blue flowers. Two strains of harebells carry recessive alleles that give the plants white flowers.

(a) Describe a cross to determine whether the white-flower causing alleles in these two strains are variants of the same gene or different genes, and the progeny phenotypes you expect to find in each case.

(b) You results from the cross above indicate that the two strains carry alleles at different genes. What phenotypic ratio do you expect to find among the F2 progeny of a cross between parents of the two strains?

Genetics Question: Please attempt only if you are familiar with GENETICS material and can explain your answers.

While performing a forward mutagenic screen in Drosophila a student indentified

two recessive mutations that cause flies to develop four wings instead of the normal two.

A. Name or describe what type of cross you would do to determine if these mutations were

an allelic series of the same gene or alleles of two different genes?

B. Describe one of the two potential outcomes of this cross in terms of progeny

phenotype(s) and what you would conclude about whether the mutations were allelic or

in separate genes base on those results.

You are given 4 true-breeding mutant strains of fruit flies, each with a different eye colour
phenotype (apricot, orange, brown & scarlet). Specific reciprocal crosses between the recessive
mutant strains produced the following results in the F1 generations:
P1: apricot female x orange male F1 : apricot males and orange females
P1: orange female x apricot male F1 : orange males and females
P1: brown female x scarlet male F1 : wildtype males and females
P1: scarlet female x brown male F1 : wildtype males and females

i) Are the four mutant phenotypes all controlled by different alleles of a single gene? Explain.

ii) Which of the mutant phenotypes, if any, are due to allelic mutations?

iii) Which of the mutant phenotypes, if any, are due to alleles of autosomal genes? Explain.

iv) Using your own symbols for the mutations, indicate the genotypes of the F1 generation males
and females in each of the crosses.

v) Which of the F1 generations when intercrossed are likely to yield recombinant phenotypes in
the F2 generations? Explain showing the expected phenotypes and their proportions. (You
may assume that Mendelâs 2nd Law of Heredity holds true for the mutations involved in this
situation. Further assume that the double mutant results in a white eye color).

vi) Predict the outcome in the F1 generations of a reciprocal cross between a truebreeding strain
with brown eyes and another with apricot eyes.