Genetics Answers

Q: Two fruitfies were crossed, one was heterozygous (Aa Bb) and another homozygous recessive. The result was flies with AB : ab = 1:1. It a case of .....

Ans: I think it should be complete linkage. Had it been independent assortment There woulsn't have been just two phenotypes/ combination but four and the ration would have been 1:1:1:1

Neither incomplete because there are not four phenotypes and they are neither in non 1:1:1:1 ratio. There was another option though epistasis(provided), this has to be ruled out. Am I right?

A woman who has two brothers, with hemophilia A and two normal sons is again pregnant. She requests counselling for the risk of her to have hemophilia. What is the risk that her next child will have hemophilia?

(1) 1 (2) 1/2, (3) 1/4. (4) 1/8

There's one right ans., I've no key available at hand.

If the father's genotype is XY then the chance should be 1/4 (a male with X'Y) but if the father is X'Y the chance is 1/2 (a female X'X' and a male with X'Y).

My question is assuming what genotype of father would be right?

I think XY, because as she is going to a counselor and the question has not considered mentioning the father so he must be, normal?

But the 1st option, is it correct? Does the tRNA's anticodon's' not align properly because they are in a loop of hairpin? Wobble occurs because of all of the following, except

(I) the anticodon is in a loop of the tRNA molecule and does align uniformly with
the codon
(2) an inosine nucleotide in the tRNA molecule can base-pair with A. C, and U
in the mRNA
(3) an inosine nucleotide in the tRNA molecule can gase-pair with A, C, and U
in the tRNA
(4) guanine can base-pair with uracil

3 is not right, so the answer should be 3 (one correct answer exists, I have no answer key at hand). But the 1st option is it correct? Does the tRNA anticodon's' not align properly because they are in a loop of hairpin?

2. A Northern Ontario Geneticist is mapping genes in Procyon lotor, also known as the common raccoon. She takes raccoon females heterozygous for each of three autosomal recessive mutations (red fur [a], no rings around eyes [b], and absence of striped tail [c]), and testcrosses them to males showing all three mutant phenotypes producing 1000 progeny of the following phenotype:
red hair, no ring, no stripe 432
WT 429
red hair, no ring 37
red hair, no stripe 35
no ring 34
no stripe33
Show the arrangement/order of alleles in the heterozygous trihybrid female parent
Draw the genetic map that explains the obtained data
Show whether or not Interference is occurring

Zaphod, a space alien from a planet near the star Betelgeuse, meets and marries a phenotypically normal Earth woman, Jane. Interestingly, Zaphod himself has a father from his home planet and a human mother. Aliens from the Betelgeus region like Zaphod have pointed noses (specified by allele Q), purple ears (specified by B), and extra long arms (specified by S). All three alleles are dominant to corresponding wild type Earth alleles. The three gene loci are located on autosomes. The three genes are known to have the linkage arrangement where gene B is in the middle of Q and S with the Q-B distance equal to 15 mu and the B-S distance equal to 20 mu. If Zaphod and Jane have children, and there is no genetic interference, what proportion will have:
A] Alien phenotypes for nose, ears and arms
B] Earth phenotypes for nose, ears and arm
C] Alien nose and arms but Earth ears
D] Alien nose, but Earth arms and ears