1. Dihybrid cross-refers to the breeding of individuals, which possesses genes for two distinct features. It is termed as dihybrid as one is considering a cross in between two distinct traits.
2. Punnett square refers to a grid system, which is used to determine the probable combinations of genes because of random fertilization. The Punnett square helps one to determine an outcome of breeding or a cross.
3. Codominance refers to the condition in which both the alleles are dominant. It comprises the alleles that exhibit the tendency of dominating at a similar time, and when an organism is heterozygotic, both the alleles are articulated.
4. Multiple alleles refer to a phenomenon in which more than two alternatives prevails for a gene.
5. Incomplete dominance refers to a condition in which none of the pair of alleles is recessive or dominant, thus, the traits get mixed in the phenotype.
1 . Dihybrid cross: Breeding of individuals which have genes for two different characteristics
2 . Meiosis: A type of cell division used to produce gametes
3 . Test cross: Breeding the individual with the dominant trait to a homozygous recessive for that trait
4 . Punnett square: A grid system used to predict possible combinations of genes due to random fertilization
A dihybrid cross is a cross between two individuals both of which are heterozygous for two genes. It takes into account of inheritance of alleles of two genes. For example, TtRr x TtRr is a dihybrid cross. A standard dihybrid cross gives the phenotype ratio of 9:3:3:1.
Meiosis is a type of cell division that forms four haploid cells from a single diploid parent cell. The daughter cells carry new gene combinations and differ genetically from the parent cell. Male and female gametes are formed when the respective germ cells undergo meiosis. For instance, meiosis in spermatogonia produce sperms, the male gametes.
A test cross is a cross wherein an individual expressing a dominant trait is crossed with a homozygous recessive individual for the same trait. The cross tells about the genotype of the dominant individual. Production of progeny with only dominant trait shows that the dominant parent was homozygous for the trait. Production of both dominant and recessive progeny reflects the heterozygosity of the dominant parent.
Punnett square is a grid structure that allows direct calculation of the probabilities of obtaining all the possible offspring of a genetic cross. It shows all the possible combinations of male and female gametes at fertilization.