Heredity and Variation: Basic Concepts

Heredity and Variation: Basic Concepts

Heredity is the phenomenon of passing on traits from parents and ancestors to their offspring. This explains why children often share similar characteristics with their parents.

Variation is the phenomenon of offspring being different from their parents and varying in many details. This variation is the driving force behind biodiversity and the basis for the process of evolution.

Gene is a segment of DNA that encodes for a specific product. Each gene can exist in multiple different states, called alleles. For example, the gene that determines flower color can have allele A (red flower) and allele a (white flower).

Trait refers to the characteristics regarding the morphology, structure, and physiology of an organism. Contrasting pairs of traits are two different states of the same trait but exhibit oppositely. For example, red flower color and white flower color are a pair of contrasting traits.

Genotype refers to the entire set of genes within an organism’s cells. Phenotype is the sum of all the trait expressions of an organism. Genotype determines phenotype.

Pure breeding refers to a line with a homogeneous genetic property, in which self-fertilization or interbreeding between them results in the following generation being uniform with only one genotype and phenotype.

Homozygous refers to individuals that have the same alleles for a gene. Heterozygous refers to individuals that have different alleles for a gene.

Pure gamete refers to gametes that are not blended with the genetic factors of parents but retain the nature of the parental gametes.

Understanding these basic concepts of heredity and variation is fundamental for studying and applying genetics in many fields such as agriculture, medicine, and biodiversity conservation.