putnamolick

Solve the systems by elimination.

2x + 4y = - 16

-2x + 2y =- 2

solve the system by elimination

6x - 10y = - 18

3x + 10y = 36

Solve the systems by graphing.

y = -2x - 8

X-Y = 5

A dominant allele H at the H locus reduces the number of body bristles that Drosophila flies have, giving rise to a “hairless” phenotype. In the homozygous condition, H is lethal. An independently assorting dominant allele S has no effect on bristle number except in the presence of H, in which case a single dose of S suppresses the hairless phenotype, thus restoring the hairy phenotype. However, S also is lethal in the homozygous (S/S) condition.

A. What is the phenotype of a dihybrid (H/h; S/s)?

B. What is the phenotype of an H/h; s/s fly?

C. Suppose you mated a H/h; s/s female with an h/h; S/s male. What phenotypic ratios would you expect in the living offspring? ****For part C I got 2/16 hairless, 7/16 hairy, and 7/16 not living

D. A true-breeding plant of genotype A/A; B/B; c/c is crossed to a truebreeding plant of genotype A/A; b/b; C/C. What would be the genotype and phenotype of the F1?

Sometimes one gene may have the effect of suppressing an abnormal (mutant) allele of another gene, resulting in the normal phenotype. Flies that are homozygous for the mutant gene, suppressor or hairy wing (s/s) will have a normal phenotype if they are also homozygous for the mutant gene, hairy wing (h/h). The following questions refer to the offspring ratios after the mating of individuals heterozygous for the wild type and mutant alleles of BOTH suppressor of hairy wing (s⁺/s) and hairy wing (h⁺/h) genes. The genes, s⁺ and h⁺ are located on separate chromosomes. Use the symbols s^D, s^R, h^D, and h^R to denote the genotype of a fly that is heterozygous for:

A. Dominant (D) mutations in both s⁺ and h⁺

B. Recessive (R) mutations in both s⁺ and h⁺

i. What phenotypic ratio of offspring would you expect if suppression occurs when you sib-mate flies heterozygous for dominant mutations in both s⁺ and h⁺ ?

ii. What phenotypic ratio of offspring would you expect if suppression occurs when you sib-mate flies heterozygous for recessive mutations in both s⁺ and h⁺ ?

iii. Draw the punnett squares showing both the genotype and corresponding phenotype for EACH of the 16 outcomes for both scenarios.

A dominant allele H reduces the number of bristles thatDrosophila flies have, giving rise to a "hairless" phenotype. Inthe homozygous condition, H is lethal. An independently assortingdominant allele S has no effect on bristle number except in thjepresence of H in which case a single dose of S supressess thehairless phenotype, thus restoring the hairy phenotype. However, Salso is lethal in the homozygous (S/S) condition

a. What ratio of hairy to harless flies would you find in thelive progeny of a cross between two hairy flies both carrying H inthe supressed condition?

b. When the hairless progeny are backcrossed with a parentalhairy fly, what phenotypic ratio would you expect to find amongtheir live progeny?

Please answer these question with explanation. Will give goodrating. Thier are parts to the questions

1a. Deaf parents, whose deafness has genetic basis, have a childwith normal hearing. Suggest two possible genetic explanations.

1b . A dominant allele H reduces the number of body bristlesDrosophila flies develop, resulting in a “hairless” phenotype. Inthe homozygous condition, H is lethal. An independently assortingdominant allele S has no effect on bristle number except in thepresence of H. In that case a single dose of S suppresses thehairless phenotype and restores hairy phenotype. However, S is alsolethal in the homozygous condition.

a) What ratio of hairy to hairless flies would you find in thelive progeny of a cross between two hairy flies both carrying the Hallele in the suppressed condition?

b) What genetic term is used to describe the effect of the Sallele on the H allele?