Plants with at least one allele D have dark green leaves, and plants with the ho
ID: 200748 • Letter: P
Question
Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves.
A homozygous dark-leaved plant is crossed with a plant with light-green leaves, and the F1 offspring is allowed to self-pollinate.
The predicted outcome of the F2 is diagrammed in the Punnett square shown in the figure, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square.
Which of the boxes marked 1-4 correspond to plants with dark green leaves?
Question 19 options:
1 only
1 and 2
4 only
1, 2, and 3
1 only
1 and 2
4 only
1, 2, and 3
Explanation / Answer
Gregor Johann Mendel proposed two laws of inheritance called Mendel’s law of inheritance
1. Law of segregation/purity of gametes
2. Law of independent assortment
Law of segregation/purity of gametes: the separation of paired allele in F1 & their entry into different gametes is called as law of segregation
When a pair of contrasting alleles governing a particular character brought together in F1, they remain together without contaminating each other and during gamete formation of F1 the two alleles segregate to each other and each allele enters into a different gamete.
The law of segregation is best studied from a monohybrid cross. In monohybrid cross in which inheritance of only one character is studied.
Tall (TT) X Dwarf (tt)
Tt X Tt (F1 self)
T t T t (Gamets)
TT (Tall) Tt (Tall) Tt (Tall) tt (Dwarf) result
The genotypic ratio= 1:2:1
The phenotypic ratio=3:1
The given question is a monohybrid cross. It is similar to above 1 (DD), 2 (Dd),3 (Dd) are plants with dark green leaves.