In the cross A/a, b/b, C/c, D/d, E/e x A/a, B/b, C/c D/d E/e in which all genes

Question

In the cross A/a, b/b, C/c, D/d, E/e x A/a, B/b, C/c D/d E/e in which all genes undergo independent assortment What proportion of offspring are expected to be homozygous for recessive alleles of genes a, b and c and e, and homozygous for dominant gene D? What proportion of the progeny will have the phenotype "AbCdE"? Show your work.: An enzyme aggase requires >16 units of activity for wild type function. Two alleles of aggase have been identified. Wild type allele A1 produces 12 units of enzyme and mutant allele A2 produces 5 units of enzyme. Which allele is dominant and which is haploinsufficient? Explain your reasoning

Explanation / Answer

Answer a:

For A locus: Aa x Aa = 1/4 of the offsprings will be homozygous for a.
For B locus: bb x Bb = 1/2 of the offsprings will be homozygous for b.
For C locus: Cc x Cc = 1/4 of the offsprings will be homozygous for c.
For D locus: Dd x Dd = 1/4 of the offsprings will be homozygous for D.
For E locus: Ee x Ee = 1/4 of the offsprings will be homozygous for e.

Proportion of offsprings expected to be homozygous for recessive alleles of gene a = 1/4.

Proportion of offsprings expected to be homozygous for recessive alleles of gene b = 1/2.

Proportion of offsprings expected to be homozygous for recessive alleles of gene c = 1/4.

Proportion of offsprings expected to be homozygous for recessive alleles of gene e = 1/4.

Proportion of offsprings expected to be homozygous for recessive alleles of gene b and c = 1/2 x 1/4 = 1/8.

Proportion of offsprings expected to be homozygous for recessive alleles of gene c and e = 1/4 x 1/4 = 1/16.

Proportion of offsprings expected to be homozygous for dominant gene D = 1/4.

Proportion of offsprings expected to be homozygous for recessive alleles of gene a,b and c and e and homozygous for dominant gene D = 1/4 x 1/2 X 1/4 X 1/4 X 1/4 = 1/512.

Answer b:

A locus: Aa x Aa = 3/4 of the offsprings will have phenotype A.
B locus: bb x Bb = 1/2 of the offsprings will have phenotype b.
C locus: Cc x Cc = 3/4 of the offsprings will have phenotype C.
D locus: Dd x Dd = 1/4 of the offsprings will have phenotype d.
E locus: Ee x Ee = 3/4 of the offsprings will have phenotype E.

Proportion of progeny that will have phenotype AbCdE = 3/4 x 1/2 x 3/4 x 1/4 x 3/4 = 27/512.

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