Heterozygous purple flower is crossed with recessive white flower. The progeny has the ratio :

Two crosses between the same pair of genotype or phenotypes in which the sources of the gametes are reversed in one cross, is known as

Write the possible genotypes Mental got when crossed F₁ tall pea plant with a dwarf pea plant

A pea plant homozygous for axial flower and constricted pods, is crossed with the pea plant homozygous for terminal flowers, having inflated pods.  Work out the cross upto F₁ generation.  Show the genotypes of the parents and phenotype and genotype of the progeny.

If a father and son are both defective in red-green colour vision, is it likely that the son inherited the trait from his father?  Comment.

Name the genetic disorder caused by trisomy of 21 st chromosome in humans.  Write the diagnostic features of the disorder.

Name the genetic disorder caused by an extra 'X' chromosome in a human male.  State the diagnostic features of the individual suffering from it.

A child has blood group O.  If the father has blood group A and mother has blood group B, work out the genotypes of the parents and the possible genotypes of the other offspring.

Let us assume in a given plant, the genotype symbol 'Y' stands for dominant yellow seed colour and 'Y' for recessive green seed colour; symbol 'R' for round seed shape and 'r' for wrinkled seeds.  Two homozygous parents (plant) with genotypes 'RRYY' and 'rryy' are crossed and their F₁ generation progeny is then 
(a) Phenotype of F₁ progeny
(b) Genotype of F₁ Progeny
(c) Gamete genotypes of F₁ progeny
(d) Phenotypic ratio of F₂ population
(e) Phenotypic ratio of yellow seeds to green seeds and round seeds to wrinkled seeds in F₂ population.