BIOL 303 Lecture 17: Chapter 7: Mendel's Principles of Continuos Variations
8 Mar 2017
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Early 1900s: how can mendel"s principles explain continuous variations? . Most trait do not produce simple ratios. Cross of a hybrid often produces a normal distribution. Environment also makes a difference to how tall you"re going to get. Two numbers are the mean and average to tell where it is and then the variations. A slow decrease near the mean and then it slows down again. Normal distribution: average is the most abundant phenotype, extremes rare. Traits are heritable, but variable - no discrete categories. Galton"s and the battle fiercely for 20 years talking about genes. Environmental factors and other genes may modify expression. Both can be multifactorial or complex due to an interaction between genes and the. Some humans can grow taller by eating a lot or for having a long allele in their gene. Polygenic traits produce a continuously varying phenotype: Dna sequences involved are termed quantitative trait loci (qtls) Influenced by interaction of genes by the environment:
