BIOL 1001 Chapter : Chapter 10 InheritancePart 2 Of 2
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Testcross is the breeding of an organism of unknown genotype with a homozygous recessive organism. Testcross for seed texture genotype: unknown could be homozygous smooth or heterozygous smooth. According to the law of independent assortment, genes for different traits are inherited independently of each other. The parental crosses that mendel did in his earlier experiments involved parental varieties that differed in a single trait (i. e. , ____________________crosses) In later experiments, mendel crossed parental varieties that differed at two traits: dihybrid cross. By using plants that were true-breeding (homozygous) for two different traits, mendel tested if trait types get sorted out together. He hypothesized that the two trait types would either be inherited together (null hypothesis), or they would be independently inherited (alternative hypothesis). If genes sort out together then the f2 will show a 3:1 phenotype. Combinations from sy and sy gametes if genes segregated together :
