Genetics and Plant Breeding

Filiation refers to the relationship between parents and their children, specifically the way in which a child is assigned to the kin group of one or both parents. Option 2 describes a residence pattern, not filiation.

It does explain the stability of populations and species over a large period of time, nonetheless evolutionary change does occur.

Human height is influenced by multiple genes acting together, which is the definition of polygenic inheritance.

Multiple alleles occur when there are more than two allelic forms of a gene occupying the same locus in a population.

According to Mendel's law of dominance, crossing a pure tall (TT) with a pure dwarf (tt) results in all heterozygous (Tt) offspring, which express the dominant tall phenotype.

A back cross is a cross between an F1 hybrid and one of its parents (or an individual genetically equivalent to one of the parents).

Allelomorphs (or alleles) are different versions of a gene that occupy the same locus on homologous chromosomes.

A pleiotropic gene is one that influences multiple, seemingly unrelated phenotypic traits. This is distinct from codominant, complementary, or supplementary genes, which describe interactions between different genes or alleles.

The gene pool represents the total collection of all genes and their associated alleles within an interbreeding population. Genome refers to the complete set of genetic material in an organism, while genotype and phenotype refer to individual genetic and physical characteristics.

Heterozygous organisms possess different alleles for a specific trait, which can lead to different genotypic combinations that may still result in the same phenotype due to dominance. Homozygous organisms have identical alleles.

The number of different gametes produced is 2^n, where n is the number of heterozygous gene pairs. For RRSsTt, the heterozygous pairs are Ss and Tt (n=2), so 2^2 = 4 types of gametes are produced (RST, RSt, RsT, Rst).

Incomplete dominance occurs when the dominant allele does not completely mask the recessive allele, resulting in a blended phenotype in the heterozygote. Here, red and white produce pink, which is the classic example of incomplete dominance.

Mendel's law of independent assortment states that alleles for different traits segregate independently during gamete formation, which leads to the creation of new combinations of traits (recombination) in offspring.

In incomplete dominance, the F2 generation phenotypic ratio is 1:2:1, reflecting the genotypic ratio because the heterozygote (the '2' in the ratio) has a distinct intermediate phenotype.