Key Concepts in Genetics

Study Notes

Homozygous: Organism with two identical alleles for a trait (e.g., AA or aa).
Heterozygous: Organism with two different alleles for a trait (e.g., Aa).
Phenotype: Observable physical traits of an organism, influenced by genotype.
Genotype: Genetic makeup or combination of alleles in an organism (e.g., PP, Pp, or pp).
Punnett Square: Tool used to predict potential allele combinations from genetic crosses.

Incomplete Dominance: A genetic inheritance pattern where neither allele is completely dominant, resulting in a blended phenotype (e.g., red and white flowers producing pink ones).
Codominance: Both alleles are expressed equally in the phenotype (e.g., black and white feathers appearing together in offspring).
Multiple Alleles: Genes with more than two allele forms affecting traits (e.g., ABO blood types).
Polygenic Traits: Traits controlled by two or more genes, contributing to a range of phenotypes (e.g., skin color).

Purebred: Offspring derived from many generations with consistent traits.
Heritage: The process of passing traits from parents to offspring.
Alleles: Different forms of a gene located at the same position on chromosomes, contributing to variations in traits.
Recessive Allele: An allele that is masked by the presence of a dominant allele; requires two copies (e.g., "aa") to be expressed.
Dominant Allele: An allele that expresses its trait in the presence of another allele (only one copy needed).

Gregor Mendel: Known as the father of genetics; his pea plant experiments established foundational principles of inheritance.
Generations:
- P Generation: The parental generation in a genetic cross.
- F1 Generation: The first generation of offspring from a genetic cross.
- F2 Generation: Offspring resulting from the interbreeding of F1 generation.

Chromosomes: Structures containing genes, present in a organism's cells; humans have 46 chromosomes in body cells and 23 in sex cells.
Meiosis: A specialized type of cell division leading to the formation of sex cells, producing cells with half the chromosome number.

Probability: Measures the likelihood of a specific genetic outcome; can be predicted using Punnett squares to evaluate potential genotypes and phenotypes in offspring.