Mendelism is study of hereditary characteristics. His pea experiments yielded following laws
Law of dominance. If a gene is dominant it will express itself above recessive gene. The recessive trait only exhibit in absence of dominant allele. But later studies show that there exists partial dominance sickle cell. Codominance ab blood group. Incomplete dominance G6PD
Law of segregation. Alleles exist as discrete units and they maintain their originality and identity in transmission. Though mutations and recombination may change it.
Law of independent assortment. Inheritance of one gene is independent from others and not dependent if other gene is inherited or not. But it is proven that genes closer on chromosome are usually inherited together.
Applications
Medico legal applications. to solve paternity dispute or solve mixing of newborns. inheritance of property. Most cases solved by ABO blood groups. Mns, duffy, kell.
Parents AA. ONLY AO
Parents AB. only A,B,O,AB
Parents A AB. Only A, B, AB. 0 over the bainton
Parents A,O. Only A, O.
Medical applications. using genetic counselling. Pedigree analysis. Inheritance of histocompatibility and inborn metabolic disorders. Rh incompatibility. RH negative mother and positive child can lead to erythroblastosis foetalis. Anti rh bovine is injectled into mother within 72 hours of delivery to prevent danger to foetus
Genetic counselling. Creating Pedigree analysis for disorders like x-linked disorder. Draw diagram.
Creating hybrid varieties for food security. Green revolution was filled by mendelism. conserving indigenous breeds. Rashtriya Gokul mission.
Meiosis
clarified that there is independent assortment but crossing over also takes place. Law of segregation is true and universal. Dominance of gene is in expression but during inheritance it is random.