In Saccharomyces cerevisae a cross involving four linked genesis made A B C D X

Question

In Saccharomyces cerevisae a cross involving four linked genesis made A B C D X a b c d, in whicch B and C are extremely closetogether in DNA. Among 200 asci, one is found to contain thespores, Abcd, abcD, ABCD, and abcd. A) what is unusual about this ascus?    i) First ask yourself what would a normalascus (unordered) look like if it were looking at the A locusalone. You should be answering this by saying how many spore showan A allele and how many show an 'a' allele?    ii)Now you should answer the same questionfor the other three loci. do any of the loci deviate from what youwould expect in a normal situtation?    iii)Next, looking at the pairs of the locithat do not deviate, are they arranged as they were in the parentallines or are they rearranged?    iv)You see four spores with chromosome (onethat links A, B, C, and D) under study. From the zygote cellentering into meiosi, what were the four chromosomes that you areseeing in the spores?    v)Why are two arranged (recombined) and twonot? In Saccharomyces cerevisae a cross involving four linked genesis made A B C D X a b c d, in whicch B and C are extremely closetogether in DNA. Among 200 asci, one is found to contain thespores, Abcd, abcD, ABCD, and abcd. A) what is unusual about this ascus?    i) First ask yourself what would a normalascus (unordered) look like if it were looking at the A locusalone. You should be answering this by saying how many spore showan A allele and how many show an 'a' allele?    ii)Now you should answer the same questionfor the other three loci. do any of the loci deviate from what youwould expect in a normal situtation?    iii)Next, looking at the pairs of the locithat do not deviate, are they arranged as they were in the parentallines or are they rearranged?    iv)You see four spores with chromosome (onethat links A, B, C, and D) under study. From the zygote cellentering into meiosi, what were the four chromosomes that you areseeing in the spores?    v)Why are two arranged (recombined) and twonot?

Explanation / Answer

If the parental combination is ABCD & abcd, theseare normal parental gametes. now we need to observe abnormalcombination (recombinants) and their no. i.e AB /aB - 1 Ac / aC - 1 Ad / aD - 2 Bd / bD - 1 Cd / cD - 1 The recombinants of Ad / aD are comparitively more which provesmaximum map distance b/w A & D and the recombinants of Bc /bCare negligible / nill which proves minimum map distance b/wBC. Thus the given combination, ABCD/abcd is the correct order

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.