1. Linkage and Gene Maps Mendelian Genetics

2. Gene Linkage Thomas Hunt Morgan discovered from his study with fruit flies, that genes are “linked” together Thomas Hunt Morgan discovered from his study with fruit flies, that genes are “linked” together 1. Each chromosome is actually a group of linked genes 1. Each chromosome is actually a group of linked genes 2. Chromosomes assort independently of one another, not genes. 2. Chromosomes assort independently of one another, not genes.

3. Crossing Over influence on Genetics Crossing over during Meiosis sometimes separates genes that had been on the same chromosome onto homologous chromosomes. Crossing over during Meiosis sometimes separates genes that had been on the same chromosome onto homologous chromosomes. Crossing over enevents occasionally separate and exchange linked genes and produce new combinations of alleles. THIS HELPS GENERATE GENETIC DIVERSITY!!!! Crossing over enevents occasionally separate and exchange linked genes and produce new combinations of alleles. THIS HELPS GENERATE GENETIC DIVERSITY!!!!

4. Gene Maps A student in Morgan’s lab, Alfred Sturtevant, wondered if rates of crossing over between genes in meiosis was a clue into gene separation. A student in Morgan’s lab, Alfred Sturtevant, wondered if rates of crossing over between genes in meiosis was a clue into gene separation. He created a gene map, which shows the locations of each known gene on one chromosome. He created a gene map, which shows the locations of each known gene on one chromosome. What he found was that the further apart two genes were on a chromosome, the more likely they were to separate during crossing over. The closer the 2 genes were, the less likely they were to separate during crossing over. What he found was that the further apart two genes were on a chromosome, the more likely they were to separate during crossing over. The closer the 2 genes were, the less likely they were to separate during crossing over.