In his first experiences, mendel he checked only one feature at a time (mono-bride), not bothering with the other features. After many experiments, Mendel continued his research and began to worry about the behavior of two traits, analyzing two characters at the same time. When verifying crosses that involved two types of traits (di-hybridism), Mendel enunciated his second law, also called independent segregation law orrecombination law.
To carry out this experiment, Mendel crossed pure pea plants originating from yellow and yellow seeds. smooth (dominant traits), with pure pea plants originating from green and wrinkled seeds (traits recessives). THE F1 generation it was entirely made up of smooth yellow seeds. The result of F1 generation it was expected, as the characteristics were dominant and the parents were pure.
Crossing of pure yellow-smooth seed with pure green-rough seed
After the first crossing, Mendel carried out a self-fertilization between the plants originated from the seeds of the F1 generation, and obtained four types of seeds as a result: plain yellow (9/16); rough-yellow (3/16); smooth green (3/16) and rough green (1/16).
F2 Generation of Mendel's Second Law
“Plain-yellow” and “rough-green” were already known phenotypes, but “rough-yellow” and “smooth-green” were not present in the paternal generation or in the F1 generation. From there, Mendel concluded that the seed color characteristic (yellow or green) is not linked to the formal characteristic of the seed (smooth or rough), that is, the color inheritance was independent of the surface inheritance of the seed.
Taking these crosses into account, we can say that in Mendel's second law the genes for one or more characters are transmitted to the gametes independently, recombining at random and forming all the combinations. possible.
Paula Louredo
Graduated in Biology
Source: Brazil School - https://brasilescola.uol.com.br/biologia/segunda-lei-mendel.htm