Two genes are said to be under linkage, or linked, when they reside in the same chromosome.Genetic mapping is the determination of the location of the genes in a chromosome. By determining the recombination frequency between several different linked genes it is possible to estimate the distance between them in the chromosome.
Independent segregation means that genes for different traits are separated out (segregated) without being influenced by other genes. A test cross is a mating between a homozygous recessive individual and an individual of unknown genotype. The genotype of the unknown parent can be deduced from the ratio of phenotypes in the F1 generation.The product rule allows you to estimate the odds that an offspring will have a certain combination of alleles for multiple genes by multiplying the probability that each separate event will occur. The farther apart genes are on a chromosome, the more frequently they will cross over. By comparison, genes that are close together on a chromosome are less likely to be separated. Analysis of how often the traits appear together helps to establish linkage maps, which show the relative positions of genes on chromosomes.
