Gene recombination | Repulsion | Coupling

The key difference between coupling and repulsion is that coupling refers to the linkage of two dominant or two recessive alleles while repulsion refers to the linkage of dominant alleles with recessive alleles. Based on his experiments, Gregor Mendel stated three laws of inheritance: the law of dominance, the law of segregation and the law of independent assortment. Law of independent assortment states that genes for different traits segregate independently of each other during the gamete formation. However, some experiments show failure in the independent assortment of genes. During the test crosses, the expected ratios are not observed. This is due to genetic linkage. Coupling and repulsion are two different aspects of linkage. Coupling refers to the linkage of two dominant or two recessive alleles while repulsion refers to the linkage of dominant alleles with recessive alleles. Problem: You have performed a dihybrid test cross for two genes (A and B). The following offspring were produced. 10 AaBb 40 Aabb 40 aaBb 10 aabb A) Are the genes of the dihybrid in coupling or in repulsion? B) What is the percent recombination between these two genes? #NikolaysGeneticsLessons #crossingOver #synapsis #linkedGenes #geneticRecombination #crossingOverInMeiosisI #crossingOverOfChromosomes #homologousChromosomes #nonsisterChromatids #sisterChromatids #MendelianGenetics #Genetics #MeiosisAndCrossingOver #crossingOverMeiosis #crossingOverBiology #mechanismOfCrossingOver #meiosis #chromatids #chiasmata #explainTheProbabilityOfCrossingOver #repulsion #coupling #Chromosome #gene #allele