If both alleles are recessive, the individual is homozygous recessive . At fertilization, gametes combine at random to form the individuals of a new generation. Illustration of Segregation of chromosomes during meiosis in the formation of gametes. He observed different genetic lines for such characteristics as flower color, plant height, seed texture, and followed their inheritance patterns for many generations to determine the basic rules of inheritance that are stil in use today. See last lecture's topic dealing with the independent assortment of chromosomes.
Pedigrees depict family relationships and indicate which ones have a particular trait.
They can reveal the mode of inheritance of a particular trait. Dentinogenesis imperfecta and what it is . Fingernails and sometimes kneecaps or elgows do not deveolop properly because of a problem with the synthesis, assembly, or degradation of collagen, a protein that makes up connective tissue. Affected people lack a critical enzyme that repairs DNA damaged by ultrafiolet light. This results in rapid and severe sunburn and skin cancer.