Why is the phenomenon of independent inheritance of traits found only in hybrids of the second generation (F2)?

| September 2, 2021 | education

1. Explain the essence of the law of splitting (Mendel’s second law). 2. Why is the phenomenon of independent inheritance of traits found only in hybrids of the second generation (F2)? 3. Name the genotypes and phenotypes of the first generation hybrids of the dihybrid crossing (F1). Write them down using the Pennett lattice. 4. Why are individuals homozygous for the dominant alleys not used in the analyzing cross to determine the genotype?

1. When heterozygous organisms are crossed, the new offspring will be different in phenotype in the ratio of 3: 1 (3 smooth peas: 1 rough), in genotype 1: 2: 1 (out of all offspring, 1 part AA: 2 parts Aa: 1 part aa).
2. The parental chromosomes have different alleles of the same gene.
3. On the example of peas: yellow smooth (AABB) and green rough (aabb) species are crossed. The phenotype of the offspring is yellow and smooth; genotype – AaBb.
4. The offspring will be with a dominant trait, which is useless information for analysis.



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