BIOL 150 Lecture Notes - Lecture 13: Gregor Mendel, Mendelian Inheritance, Allele Frequency
Document Summary
Green seeds disappear in first generation, but reappear in second. Mendel"s law of segregation - organisms have two genetic elements that separate when gametes are formed (what we know today as meiosis the separation of homologous chromosomes). Mendel"s law of independent assortment: during gamete formation, gene pairs assort independently of one another. Mendel essentially showed that the proportion of recessive alleles remains constant in a population (short term). Mendel"s conclusion- inheritance does not involve blending of characteristics the f1 generation must have held the ele. Frequency of recessive alles remains constant without evolutionary pressure. Lamarck (in 1809) was the first to propose a mechanism for evolution: the inheritance of acquired characteristics. Individuals evolve in response to environment; pass changes to offspring. Darwin & wallace understood that individuals do not evolve. The going thought at the time (1908) was that dominant alleles increase in frequency when gametes combine at random (mendel showed this to not be true).