Final answer:
Chromosome maps based on recombination frequencies are known as genetic maps. They utilize the process of crossing over to calculate the genetic distances between genes. Alfred Sturtevant's contributions in this area helped establish map units, or centimorgans, to quantify these distances.
Step-by-step explanation:
Chromosome maps constructed using recombination frequencies are called genetic maps. These maps are created by using the natural process of recombination to measure the genetic distance between different genes. To assist in understanding this concept, chromosome mapping involves the use of recombination frequencies to establish the relative positions of genes on a chromosome. The construction of genetic maps is facilitated by observing the crossover of genes during genetic recombination, which can be calculated as the proportion of offspring that exhibit nonparental genotypes.
A key point to remember is that genetic recombination primarily occurs through the process of crossing over during meiosis. Alfred Sturtevant, an early geneticist, used this principle to create genetic maps, where he introduced the concept of map units or centimorgans (cM), with 1 cM representing a recombination frequency of 1%. Sturtevant's work showed that genes closer to one another are less likely to cross over, and thus, have a lower recombination frequency, whereas genes that are further apart have a higher chance of crossing over.