Genetics Fundamentals

Study Notes

Genetics is the study of variations and how they are transferred from one generation to another.
Gregor Johann Mendel is considered the father of genetics.

Heredity: the transmission of traits from one generation to another.
Variation: the difference observed among members of the same species and also among offspring of the same parent.
Gene: the unit of inheritance, which is transferred from parent to offspring, controlling the expression of a character.
Allelomorphs: every character is controlled by two genes, which control contrasting expressions.
Allele: a pair of genes that controls contrasting characters and lies on the same loci in homologous chromosomes.
Dominant allele: an allele that expresses itself in the presence of its contrasting allele.
Recessive allele: the allele that cannot express itself in the presence of the dominant allele.
Homozygous organism: an individual with similar alleles of a character.
Heterozygous organisms: an individual with dissimilar alleles of a character.
Phenotype: the physical expression of a character.
Genotype: represents how an organism is genetically made up.

F1 generation: the first filial generation produced when two pure parents are crossed.
F2 generation: the second filial generation of progeny formed when two F1 generation plants are crossed.

Mendel performed experiments on a garden pea (Pisum sativum) with different visible contrasting characters.
He selected seven contrasting pairs of characters or traits in a garden pea.
Mendel's experiment involved three stages: selection of parents, production of F1 plants, and production of F2 plants.
True breeding plant: a plant that produces an offspring with the same characteristics on self-pollination.