Why do mapping experiments become less accurate when the dis

Why do mapping experiments become less accurate when the distances between genes become large? See Section 7.4 Crossover gametes become less common. Interference is greater when the distance between genes is large. Multiple-strand exchanges are more common. Recombination occurs less frequently in long chromosomes.

Solution

Multiple strand exchanges are more common when the distance between genes become large and so the mapping experiment becomes less accurate. Gene mapping experiments involves determining the position of gene on a chromosome as well the distance between two genes. Genes that are inherited together (linked genes) are situated closely on such maps while those which are not linked to each other (for eg: genes from different chromosomes) and not dependent on any other gene for inheritance are distant Genes present on the same chromosome can be separated from each other during meiosis which leads to formation of sperm or egg cells. The genes are separated from each other in a process called as crossing over wherein a part of chromosome breaks and exchanges it with the other gene of the homologous chromosome.The longer apart the two genes are on the chromosome, the more frequently such an exchange will occur between them. When the crossing over happens at more than two points in the homologous chromosome, it is known a smultiple crossng over or multiple strand exchange.