BIOL 101 Lecture Notes - Lecture 6: Gregor Mendel, Pea, Punnett Square
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First to comprehend basic principles of genetics. Each trait = 2 versions (alleles: dominant, recessive. Plants: good study organism: easy to manually fertilize, collect offspring, fast breeders, easily categorized traits: shape, color. Each only 2 variants, unambiguous: true-breeding: bred populations particular trait. Remove pollen-bearing stamens so it couldn"t self fertilize. Flower position [d: on stem, r: at tip] Genotype [pp] = underlying the phenotype is the genetic composition. Pea plants- flower color p = dominant p = recessive. Dominant: expressed in the heterozygous condition: ex: yellow peas in yy. Recessive: not expressed in the heterozygous condition: ex: green pea allele masked in yy. Genotype = underlying the phenotype is the genetic composition. In a 2 allele system you have 3 possible phenotypes: homozygous dominant (aa, heterozygous (aa, homozygous recessive (aa) Aa x aa = aa, aa x aa = aa. [aa x aa, aa x aa, aa x aa, aa x aa] 4 crosses.
