The map of a chromosome interval is:A——10 m.u.——B——40 m.u.——CFrom the cross A b c / a B C × a b c / a b c, how many double crossovers would be expected out of 1000 progeny, if no interference is present?Question 11Answera.20b.40c.5d.10e.80
Question
The map of a chromosome interval is:A——10 m.u.——B——40 m.u.——CFrom the cross A b c / a B C × a b c / a b c, how many double crossovers would be expected out of 1000 progeny, if no interference is present?Question 11Answera.20b.40c.5d.10e.80
Solution 1
The calculation of double crossovers is based on the product of the probabilities of the single crossovers.
The map shows that the distance between A and B is 10 map units (m.u.) and the distance between B and C is 40 m.u.
The probability of crossover between A and B is 10/100 = 0.1 (since 1 m.u. = 1% recombination) and the probability of crossover between B and C is 40/100 = 0.4.
The probability of double crossover (crossover between A and B and between B and C) is the product of the individual probabilities, which is 0.1 * 0.4 = 0.04.
Therefore, out of 1000 progeny, the expected number of double crossovers is 0.04 * 1000 = 40.
So, the answer is b. 40.
Solution 2
The calculation of double crossovers is based on the product of the probabilities of the single crossovers that it comprises.
In this case, the single crossovers are A-B and B-C.
The probability of an A-B crossover is 10 m.u., or 10%, and the probability of a B-C crossover is 40 m.u., or 40%.
To find the expected number of double crossovers, multiply these probabilities together and then multiply by the total number of progeny.
So, (0.10) * (0.40) * 1000 = 40.
Therefore, the answer is b. 40.
Similar Questions
To construct linkage maps, scientists estimate the distance between genes on the same chromosome based on the ______, as indicated by the percentage of recombinant offspring.Multiple choice question.number of chromosomesnumber of gametes producedcrossover frequencytime for meiosis to be complete
The cross L p q / l P Q × l p q / l p q is carried out. If the L gene is in the middle, between genes P and Q, what would be the genotypes of the double crossover gametes in this cross?Question 12Answera. L p q and l P Qb.L P Q and l p qc.L p Q and l P qd.cannot be determinede. l p Q and L P q
Two chromosoms A 10101010 B 01010101A two point crossover operation in-between positions 3 and 8 should be performed to give two new chromosoms. Which constellation is the crossover result? 10110100 01001011 10010101 01101010 01010100 10101011
ap distance in cM can be estimated:Question 7Answera.by the number of parental offspring observed in a testcross divided the total number of offspringb.by the number of recombinant offspring observed in a testcross divided by 2c.by the number of recombinant offspring observed in a testcross divided the total number of offspringd.by the number of parental offspring observed in a testcross divided the number of recombinant offspringe.by the number of recombinant offspring observed in a testcross divided the number of parental offspring
To construct linkage maps, scientists estimate the distance between genes on the same chromosome based on the ______, as indicated by the percentage of recombinant offspring.
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.