Genetics Vocabulary Study Guide

This flashcard set covers essential genetics vocabulary, inheritance patterns, chromosomal abnormalities, and tools for genetic analysis like Punnett squares and pedigrees.

Gene

The basic unit of heredity that occupies a specific location on a chromosome.

Homozygous

Having two identical alleles for a particular gene (e.g., $AA$ or $aa$).

Genotype

The genetic makeup of an organism, represented by allele combinations.

Phenotype

The observable physical characteristics or traits of an organism.

Allele

Different forms or versions of a gene.

Dominant

An allele that is expressed over a recessive allele; it masks the recessive trait.

Recessive

An allele that is only expressed in the phenotype when two copies are present ($aa$).

Heredity

The passing of genetic traits from parents to offspring.

Gametes

Reproductive cells, including both male (sperm) and female (egg) sex cells.

Hybrid

An offspring of parents with different traits, often associated with a heterozygous genotype.

Codominance

A type of inheritance where both alleles are fully and simultaneously expressed in the phenotype.

X-linked

Refers to genes or traits located specifically on the X chromosome.

Carrier

An individual who has one recessive allele for a trait but does not express that trait in their phenotype.

Autosomes

Any chromosome that is not a sex chromosome.

Trisomy

A condition where there are three copies of a specific chromosome instead of the normal two.

Monosomy

A condition where there is only one copy of a specific chromosome instead of the normal pair.

Incomplete dominance

A type of inheritance where one allele is not completely dominant over another, resulting in a blended phenotype.

Nondisjunction

The failure of chromosomes to separate properly during cell division.

Mutation

A change in the DNA sequence of an organism; they are not always harmful and can contribute to natural selection.

Monohybrid cross

A genetic cross used to study the inheritance of a single trait.

Dihybrid cross

A genetic cross used to study the inheritance of two different traits simultaneously.

Zygote

The diploid cell produced by the fusion of male and female gametes.

Fetus

The developing offspring in the later stages of prenatal development, following the embryo stage.

Karyotype

A visual representation of an individual's full set of chromosomes, used to detect genetic disorders.

Klinefelter's syndrome

A genetic condition in males caused by the presence of an extra X chromosome ($XXY$).

Turner Syndrome

A genetic condition in females caused by a missing or partially missing X chromosome ($XO$).

Down's Syndrome

A genetic disorder caused by the presence of an extra 21st chromosome, known as trisomy 21.

Pedigree

A diagram or family tree used to track the occurrence of specific traits or genotypes across multiple generations.

Polygenic

An inheritance pattern where a single trait is controlled by two or more different genes.

Deletion

A type of mutation where a part of a DNA sequence or a chromosome is lost.

Translocation

A type of mutation where a segment of a chromosome breaks off and attaches to a different, non-homologous chromosome.