LIFE 102 Lecture Notes - Lecture 14: Punnett Square, F1 Hybrid, Zygosity
25 Oct 2016
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Document Summary
From his results, mendel produced a model that could predict the results of genetic crosses. Mendel"s conclusions: there is variation in the factors that accounts for variations in inherited traits. This is mendel"s first law: segregation of factors/alleles into gametes. You cannot detect segregation of alleles until the f1 generation makes gametes which then fuse to make the f2. Homozygous: the presence of two identical alleles (as in the true-breeding parent lines) e. g. aa or aa. Heterozygous: the presence of two different alleles (as in the f1 hybrid) aa. Genotype: the combination of alleles in an organism (homozygous dominant, homozygous recessive or heterozygous) represented by allele letters. Phenotype: the observable appearance of an organism (note you only see the recessive. If you see the dominant phenotype, you don"t know if the genotype is homozygous dominant or heterozygous. If the offspring of this cross gives any recessive phenotypes, the original unknown genotype is heterozygous.
