In: Biology
1. Which of the following statements is FALSE?
Crossover interference is greater over short distances.
With complete crossover interference, at most 1 crossover can occur between two genes.
Recombination frequency is an overestimate of map distance.
Crossover frequency is a good measure of distance even between genes that recombine at a frequency of 50%.
2. Which of the following statements is TRUE?
Physical distance between genes is always proportional to map distance.
Crossovers occur at a lower frequency in gene-rich regions.
Individuals in a true-breeding population must have identical genome sequences.
The test cross design makes it possible to deduce the genotype of progeny from their phenotype.
3. Which of the following statements is FALSE?
Recombination frequency is a poor measure of distance between genes that recombine at a frequency of 50%.
The map distance between any two genes is equal to the frequency at which they recombine.
In a given occurrence of meiosis, a double-crossover can lead to 4 recombinant gametes.
Cis and trans configurations show no significant differences in recombination frequencies.
1. option A and D are FALSE. Crossovers occur more between genes at longer distance.
2. option D is TRUE. Test cross helps finding the genotype, specially in case of difference between homozygous dominant and heterozygous genotype.
3. option A and C are FALSE. Double crossover forms 2 recombinant gametes. Recombination upto 50% gives correct approximate measure of distance between the genes.