Wth

Figure 2.3 Mendel self-pollinated (indicated by curved arrows) the F2 progeny produced by the cross shown in Figure 2.2. Of the F2 progeny that had a yellow phenotype (three-quarters of the total), one-third produced all progeny with a yellow phenotype and two-thirds produced progeny with a 3:1 ratio of yellow and green progeny (or three-quarters yellow progeny). Individuals are represented by diamonds since pea plants are hermaphrodites.

Figure 2.3 Mendel self-pollinated (indicated by curved arrows) the F2 progeny produced by the cross shown in Figure 2.2. Of the F2 progeny that had a yellow phenotype (three-quarters of the total), one-third produced all progeny with a yellow phenotype and two-thirds produced progeny with a 3:1 ratio of yellow and green progeny (or three-quarters yellow progeny). Individuals are represented by diamonds since pea plants are hermaphrodites.

meaning of the dominating trait as a hybrid and as a parental trait" (quoted in Orel 1996). During his work, Mendel employed the terms "dominating" (which became dominant) and "recessive" to describe the manifestation of traits in impure or heterozygous individuals.

With the benefit of modern symbols of particulate heredity, we could diagram Mendel's monohybrid cross with pea color in the following way.

P1 Phenotype Genotype Gametes produced

F1 Phenotype Genotype Gametes produced

Yellow x green GG gg Gg

All "impure"yellow

A Punnett square could be used to predict the pheno-typic ratios of the F2 plants:

and another Punnett square could be used to predict the genotypic ratios of the two-thirds of the yellow F2 plants:

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