Unit 9- Genes, Chromosomes, and Inheritance

These flashcards cover key concepts related to genes, chromosomes, and inheritance, including definitions and processes relevant to genetics.

Genotype

The genetic makeup of an organism, describing the alleles an individual carries.

Phenotype

Observable traits of an organism, determined by genotype and environment.

Homozygous

An organism with two identical alleles for a trait (e.g., AA or aa).

Heterozygous

An organism with two different alleles for a trait (e.g., Aa).

Polymorphisms

Natural genetic differences in populations that are heritable but do not necessarily cause disease.

Point mutations

Small-scale mutations involving a single base-pair change in DNA.

Silent mutation

A point mutation that does not result in an amino acid change.

Missense mutation

A point mutation that results in an amino acid substitution.

Nonsense mutation

A point mutation that produces a premature STOP codon, truncating the protein.

Frameshift mutation

Insertion or deletion of 1-2 bases that shifts the reading frame, usually resulting in a nonfunctional protein.

Gene duplication

A large-scale mutation where a segment of DNA is copied, resulting in extra gene copies.

Meiosis

The process that reduces chromosome number and produces haploid gametes (sperm/egg).

Crossing over

The exchange of genetic material between homologous chromosomes during Prophase I of meiosis.

Gametes

Haploid reproductive cells (sperm or egg) produced through meiosis.

Complete Dominance

A pattern of inheritance where one allele completely masks the expression of another.

Incomplete Dominance

A pattern of inheritance where the phenotype of heterozygotes is an intermediate of the two homozygous phenotypes.

Codominance

A pattern of inheritance where both alleles in a heterozygote are fully expressed.

Independent Assortment

The principle that alleles of different genes segregate independently during gamete formation.

Incomplete Penetrance

When not all individuals with a genotype show the expected phenotype.

Variable Expressivity

When the same genotype produces varying phenotypes in different individuals.

Epistasis

A genetic interaction where one gene affects the expression of another gene.

Environmental Influence

The impact of environmental factors on the expression of traits.