The recombination frequency between two genes is always less than 50% because the probability of their breaking apart is higher than when they are coming together.
A gene contains nucleotide sequences that encode instructions for an organism’s proteins and enzymes.
Gene expression allows cells to make these proteins, but it only occurs in controlled environments such as cell culture or tissue culture.
In order to prevent spontaneous mutation that might happen in nature, recombinations can be restricted or prevented using molecular markers that are unique to each gene—or else a single sequence with multiple alleles.
Alleles are different versions of the same gene; for example, the ABO blood groups (a locus on chromosome 15) contain three alleles: A, B and O.
Because recombination between genes is not allowed in cell culture, identical sequences can be induced to recombine by using genetic engineers to equip them with markers (molecules that are unique to a particular gene) that can be easily distinguished from each other.
The availability of a marker allows the frequency of recombination between genes from different populations to be calculated. Recombination is the mechanism by which new alleles may arise and spread through a population, but it is also useful for calculating the frequency at which two closely related alleles will recombine after a single crossover event in the absence of polymorphism.
Which statement explains why the recombination frequency between two genes is always less than 50%?
- The probability of their breaking apart is higher than that of their coming together.
- The alleles are identical to each other.
- The two alleles are present in the same chromosome.
- Allelic recombination is always restricted to the ends of chromosomes.
- The amount of genetic material exchanged is not compatible with the presence of a marker that distinguishes them.
Recombination Frequency :
1. The probability of their breaking apart is higher than that of their coming together.
Alleles are identical to each other. This statement explains the why the recombination frequency is always less than 50%. The probability of their breaking apart is higher than they are coming together.
2. The alleles are identical to each other.
The alleles are not identical to each other, thus, this statement does not explain why the recombination frequency between two genes is always less than 50%.
3. The two alleles are present in the same chromosome.
The alleles are not present in the same chromosome, thus, it cannot explain why the recombination frequency between two genes is always less than 50%.
4. Allelic recombination is always restricted to the ends of chromosomes.
Allelic recombination must not be restricted to the ends of chromosomes, therefore, this statement does not explain why the recombination frequency between two genes is always less than 50%.
5. The amount of genetic material exchanged is not compatible with the presence of a marker that distinguishes them.
The amount of genetic material exchanged is not compatible with the presence of a marker that distinguishes them, therefore, this statement does not explain why the recombination frequency between two genes is always less than 50%. Conclusion: The correct answer is option 1. The recombination frequency between two genes is always less than 50% because the probability of their breaking apart is higher than when they are coming together.
6. The recombination frequency between two genes is always less than 50% because the probability of their breaking apart is higher than when they are coming together.
The recombination frequency between two genes is always less than 50% because the probability of their breaking apart is higher than they are coming together. This statement explains why the recombination frequency between two genes is always less than 50%. One of the methods used to determine recombination between the genes is the percentage of homozygous genotypes in a population. If you have a sample of “n” number of individuals and the percentage is lower than 50%, then there is evidence for recombination in that population.
Genetic mapping and molecular linkage analysis involve the use of genetic markers to determine genetic recombination between two genes, or map each gene relative to one another. Genetic markers can be used as “jumping off points” for mapping and are used to calculate genetic recombination frequency. A locus is a region on a chromosome that contains specific gene markers; each gene marker has its own locus, which indicates its place on the chromosome map.
7. Which of the following is NOT one of the main uses of genetic markers?
- To calculate recombination frequency between two genes
- To locate a specific gene on a chromosome map
- To determine the order and distance between two genes
- To find out if any mutations (genetic changes) have happened in a population
- A major use of genetic markers is to:
- Calculate the recombination frequency between two genes.
- Locate a specific gene on a chromosome map
- Determine the order and distance between two genes that are close together on a chromosome
