Question

The pedigree below diagrams the inheritance pattern of pea pod color over three generations. according to the pedigree, why do all of the f1 generation individuals exhibit a yellow pea pod phenotype?

Answer 1

All F1 individuals in the pedigree of pea pod color have a yellow phenotype because yellow is the dominant allele. The P generation's true-breeding yellow (YY) plants crossed with the green (gg) plants results in F1 plants with a genotype of Yg, expressing the yellow color due to dominance.

Step-by-step explanation:

In the pedigree diagram of pea pod color inheritance, all of the F1 generation individuals exhibit a yellow pea pod phenotype because yellow is the dominant trait and green is recessive. The P generation involves true-breeding plants, meaning the yellow pea plants have two dominant alleles (YY) while the green pea plants have two recessive alleles (gg). When these true-breeding plants are crossed, the F1 generation inherits one dominant and one recessive allele (Yg), which results in a yellow phenotype due to the dominance of the yellow allele.

Mendelian genetics explains that in such a monohybrid cross, a dominant trait will always express itself over a recessive trait when present. Therefore, even though the F1 plants have one recessive allele, they exhibit the yellow phenotype. Furthermore, Punnett square analysis can predict that the F2 generation will have a phenotypic ratio of 3:1, with three quarters exhibiting the dominant yellow phenotype and one quarter exhibiting the recessive green phenotype following the law of segregation.