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Unformatted text preview: Foundations of Genetics Heredity How we inherit our various characteristics (DNA) genetics g study of how genes are passed to next generation A scientist and monk, Gregor Mendel , in the 1800s was the first to actually count numbers of offspring in crosses. About the same time as Darwin didnt know each other; was a naturalist too (both very interested in the natural world); monk Breeding; chose peas for his experiments father of genetics . Known for this after his death; observed that plants & animals inherited characteristics from BOTH of their parents (never heard of chromosomes, etc) trying to show this in a scientific way Very good at math showed statistically the crosses of these pea plants Pea plants had both male & female parts on the flower Controlled cross take male part out of one plant and put it in another plant easy to self fertilize in a baggy or cross fertilize (male parts can be removed) Looked for plants for true breeding purple & white flowers; would breed them until purple flowers would only breed purple; same for white PURE BREEDING CROSSES white & purple all became purple SELF FERTILIZATION 3 Purples: 1 White Mendel's Experimental Design ( image ) The garden pea Fig 11.2 true-breeding varieties Fig 11.3 P or parental generation 1 st generation (P is abbreviation) F1 generation or first filial (coming from the same set of parents) generation. F2 generation. Comes from F1 Used seven pairs of contrasting traits. Table 11.1 T dominant trait Purple bc it showed up and white didnt recessive . trait White flower bc it didnt show up until later on 3:1 dominant to recessive phenotype in the F2 generation. 3 Purple flowers: 1 White flower P & W (P generation) cross fertilize make P (F1 Generation) P self-fertilizes makes 3P: 1W (F2 Generation) P true-breeding dominant F3 Generation 4 P 2P not-true breeding dominant 3P:1W 1P true-breeding recessive 4W of plants are purple; plants are white...
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