Chromosomes, linkage and recombination

Question 1

The first linkage maps

Answer 1

The first linkage maps were developed by Alfred Sturtevant in 1913. Sturtevant used the fruit fly Drosophila melanogaster to study inheritance patterns of different traits and genes. He observed that genes located on the same chromosome tend to be inherited together, which suggested that the chromosome was the physical unit of inheritance

Sturtevant used this observation to construct the first genetic map, which showed the relative positions of different genes on a chromosome. He measured the frequency of crossing over between pairs of genes, which allowed him to determine the distance between them on the chromosome

Question 2

Recombination and the spread of new genetic variants

Answer 2

Double recombinants are individuals that result from two crossovers between linked genes

If two genes are closely linked, they are less likely to undergo a double crossover event, whereas if they are further apart, the probability of a double crossover event increases

Recombination is a critical mechanism that contributes to genetic diversity in populations. It is the process by which genetic information is exchanged between chromosomes during meiosis, leading to the formation of new combinations of alleles in the offspring

Recombination allows for the creation of new genetic variants and their spread through populations, as these variants can be passed onto offspring