Principles of Inheritance and Variation Test - 4

In monohybrid and dihybrid cross F2 generation is obtained by selfing of Fi hybrids as male and female.

"Experiments on Plant Hybridization" is a seminal paper written in 1865 and published in 1866 by Gregor Mendel, an Augustinian friar considered to be the founder of modern genetics. The paper was the result after years spent studying genetic traits in Pisum sativum, the pea plant. Mendel read his paper to the Natural History Society of Brünn. It was published in the Proceedings of the Natural History Society of Brünn the following year.

In dihybrid cross, two new kinds of plants with new trait are formed. This is possible only when all traits assort independently and recombine to form new combination.

If a heterozygous yellow seeded plant is crossed with green seeded plants, the ratio of yellow and green seeded plants are 50:50 or 1:1 similar to test cross.

In a cross between a pure tall plant with green pod and a pure short plant with yellow pod four short plans are produced in F2 generation as shortness is recessive trait and appear only in homozygous condition.

Mendelian experiments were successful as garden pea was true breeding having different contrasting trats, can be grown in any season. He kept the record statically to come at conclusion.

The test cross is used to determine the genotype of the plant in which F1 plant is crossed with homozygous recessive plants. If the ratio is 1:1 the plant is homozygous.

The heterozygous individual produce two kinds of gametes as during gametes formation allele separate from each other and passes two different gametes. Both the alleles are different from each other so, produce two different kind of gametes.

The principles that govern heredity were discovered by a monk named Gregor Mendel in the 1860's. One of these principles, now called Mendel's law of segregation, states that allele pairs separate or segregate during gamete formation, and randomly unite at fertilization.

Mendel’s findings were rediscovered by three scientist doing the same experiment separately after 20 years of Mendel’s finding. They were De vries, Correns and Tschermak.