Deduce the phenotypic proportions in the progeny of thefollowing crosses of autotetraploids. Assume that the fourhomologous chromosomes of any one type pair randomly two-by-two andthat only one copy of the a+ allele is necessary for the wild-typephenotype. A. a+a+aa x aaaa B. a+aaa x aaaa C. a+aaa x a+aaa D.a+a+aa x a+aaa

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Trinidad TremblayLv2

28 Sep 2019

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1. In the flour moth, Ephestia, pigment production in eyes of moths depends on a pair of nuclear alleles, A and a. The A allele directs production of a diffusible substance that his involved in pigment synthesis. This substance diffuses from a heterozygous or homozygous dominant mother into all her young, enabling them to synthesize the final pigment. All progeny of a dark-eyed female have dark eyes initially. As the moths age, only those with an AA or Aa genotype can make the diffusible substance for themselves and continue to produce pigment. Without the diffusible substrate, pigment is no longer produced and the eyes lighten with age. What eye color do you expect in young progeny, and then as they age, from each of these crosses? a) Female AA X Male AA b) Female AA X Male Aa c) Female AA X Male aa d) Female Aa X Male AA e) Female Aa X Male Aa f) Female Aa X Male aa g) Female aa X Male AA h) Female aa X Male Aa i) Female aa X Male aa

In the flour moth, Ephestia, pigment production in eyes of moths depends on a pair of nuclear alleles, A and a. The A allele directs production of a diffusible substance that his involved in pigment synthesis. This substance diffuses from a heterozygous or homozygous dominant mother into all her young, enabling them to synthesize the final pigment. All progeny of a dark-eyed female have dark eyes initially. As the moths age, only those with an AA or Aa genotype can make the diffusible substance for themselves and continue to produce pigment. Without the diffusible substrate, pigment is no longer produced and the eyes lighten with age.

What eye color do you expect in young progeny, and then as they age, from each of these crosses?

a) Female AA X Male AA

b) Female AA X Male Aa

c) Female AA X Male aa

d) Female Aa X Male AA

e) Female Aa X Male Aa

f) Female Aa X Male aa

g) Female aa X Male AA

h) Female aa X Male Aa

i) Female aa X Male aa

Drosophila diploid 2n=8 tolerate trisomy and monosomy of their smolest chromosome 4 so all trisomic and monosomic for this chromosome are viable. However, nullisomic and tetrasomics for chromosome 4 are letal and this type of progeny never born.

Consider the segment polarity gene cubitus interruptus (ci), that affets cuticle characteristics (mutant has naked cuticle) and also alters the wing vein pattern. Consider that ci recessive mutations results in vein interraption in the wing while the ci+ wild type allows the normal vein pattern in the wing. Deduce the phenotypic proportions in the progeny of the following crosses involving trisomcs. What are the expected phenotypes and genotypes of the progeny from these different fly crosses?

Assume tat the presence ofone wild type ci+ allele is sufficient to confer the wild type wing vein pattern phenotype.

write the diagramm of the cross, genotype, phenotype

for F1 - genotypic and phenotypic ratio - # wild type (split as # diploid # trisomic or # ?) : # mutant (split as # diploid # trisomic or # ?)

1) ci+/ci+/ci x ci+/ci

2) ci/ci/ci x ci+/ci/ci

3) ci+/ci/ci x ci+/ci