Name: Fossils as Evidences of Evolution
Uploaded: 2019-07-19
Duration: 3 min 32 s
Description: Fossil remains have been found in rocks of all ages and are of the simplest organisms found in the oldest rocks, as well as fossils of more complex organisms.

Question

Study Mendel's cross between two plants with a pair of contrasting characters. RRYY x rryy (Round Yellow x Wrinkled Green). He observed 4 types of combinations in F₂, generation. Which of these were new combinations? Why do new features which are not present in the parents, appear in F₂, generation?

Accepted Answer

In Mendel's classic experiments on inheritance, one of the key principles he discovered was the Law of Independent Assortment, which explains how genes for different traits segregate independently during gamete formation. To illustrate this principle, let's consider Mendel's cross between two plants with a pair of contrasting characters: Round Yellow (RRYY) and Wrinkled Green (rryy).

Now, let's examine the combinations observed in the F₂ generation:

Round Yellow (RRYY).

Round Green (RRyy)

Wrinkled Yellow (rrYY)

Wrinkled Green (rryy)

The new combinations observed in the F₂ generation are "Round Green" (RRyy) and "Wrinkled Yellow" (rrYY). These combinations were not present in the parental generation and represent the result of the independent assortment of alleles during gamete formation.

These new combinations arise due to Mendel's Laws of Independent Assortment and Segregation, which lead to genetic diversity in the offspring.

Law of Independent Assortment: This principle states that alleles (gene variants) for different traits segregate independently during gamete formation. In this case, the alleles for seed shape (Round or Wrinkled) segregate independently of the alleles for seed colour (Yellow or Green). Each combination of seed shape and colour is equally likely in the offspring, leading to the appearance of new combinations not present in the parents.

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