When crossing corn plants with smooth colored seeds and plants with wrinkled unpainted seeds, all hybrids of the first generation had smooth colored seeds. From the analyzing crosses of F1 hybrids, 3800 plants with smooth colored seeds were obtained; 150 – with wrinkled painted; 4010 – with wrinkled unpainted; 149 – with smooth unpainted. Identify the genotypes of parents and offspring resulting from the first and analyzing crosses. Make a diagram of the solution to the problem. Explain the formation of four phenotypic groups in analyzing crosses.
1) First crossing:
P AABB × aabb
G AB × ab
2) Analyzing crosses:
P AaBb × aabb
G AB, Ab, aВ, ab × ab
AaBb – smooth colored seeds (3800);
Aabb – smooth unpainted seeds (149);
aaBb – wrinkled colored seeds (150);
aabb – wrinkled unpainted seeds (4010);
3) the presence in the offspring of two groups of individuals with dominant and recessive characters in approximately equal proportions (3800 and 4010) is explained by the law of linked inheritance of characters. Two other phenotypic groups (149 and 150) are formed as a result of crossing over between allelic genes.
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