Term: Alleles
Definition: Different forms of a gene that occupy the same position (locus) on homologous chromosomes.

Term: Amniocentesis
Definition: A medical procedure used to collect amniotic fluid from a pregnant woman to test for genetic abnormalities in the fetus.

Term: Aneuploidy
Definition: A condition where the number of chromosomes is not the typical set for a species, such as an extra or missing chromosome.

Term: Barr body
Definition: The inactivated X chromosome in the cells of female mammals, visible as a dense structure in the nucleus.

Term: Blending inheritance
Definition: An outdated theory that offspring are a blend of the traits of their parents.

Term: Chromosomal theory of inheritance
Definition: The theory that genes are located on chromosomes, which are the basis for inheritance.

Term: Chorionic villi sampling (CVS)
Definition: A prenatal test where a small sample of placental tissue is collected for genetic testing.

Term: Continuous variable
Definition: A variable that can take on an infinite number of values, such as height or weight.

Term: Cross-fertilization
Definition: Fertilization between two different individuals, leading to genetic variation.

Term: Crossing over (recombination)
Definition: The exchange of genetic material between homologous chromosomes during meiosis, leading to new combinations of alleles.

Term: Codominant
Definition: A genetic scenario where both alleles in a heterozygous individual are fully expressed, without one being dominant over the other.

Term: Dominant pedigree
Definition: A pedigree in which a dominant trait appears in every generation.

Term: Dosage compensation
Definition: A mechanism that balances the dose of X chromosome gene expression in males and females.

Term: Dihybrid cross
Definition: A genetic cross that follows two traits simultaneously, involving organisms heterozygous for both traits.

Term: Dominant
Definition: An allele that masks the effect of a recessive allele in a heterozygous organism.

Term: Epigenetic inheritance
Definition: Inheritance of traits that are controlled by factors other than changes in the DNA sequence, such as DNA methylation.

Term: Epistasis
Definition: Interaction between gene pairs where one gene can mask or modify the expression of another gene.

Term: First filial (F1) generation
Definition: The first generation of offspring from a cross between two parental individuals.

Term: Genetic mapping
Definition: The process of determining the location of genes on a chromosome.

Term: Genome-wide association study (GWAS)
Definition: A study that looks for associations between specific genetic variations (SNPs) and particular diseases across a population.

Term: Genomic imprinting
Definition: A form of inheritance where certain genes are expressed differently depending on whether they are inherited from the mother or father.

Term: Genotype
Definition: The genetic makeup of an organism, specifically the combination of alleles it carries.

Term: Heterozygous
Definition: Having two different alleles for a particular gene.

Term: Homozygous
Definition: Having two identical alleles for a particular gene.

Term: Human genome maps
Definition: Charts that show the location of genes on human chromosomes.

Term: Incomplete dominance
Definition: A genetic scenario where the phenotype of a heterozygote is intermediate between the phenotypes of the two homozygotes.

Term: Maternal inheritance
Definition: Inheritance of traits specifically from the mother, often associated with mitochondrial DNA.

Term: Multiple alleles
Definition: The existence of more than two alleles for a particular gene within a population.

Term: Multiple crossovers
Definition: When more than one crossover event occurs between homologous chromosomes during meiosis, leading to greater genetic variation.

Term: Monohybrid cross
Definition: A genetic cross that involves one trait, where organisms are heterozygous for that trait.

Term: Monosomy
Definition: A condition where an individual has only one copy of a particular chromosome instead of the typical two.

Term: Nondisjunction
Definition: An error in cell division where chromosomes fail to separate properly, leading to an abnormal number of chromosomes in the resulting cells.

Term: Parental generation
Definition: The original individuals in a genetic cross from which offspring are derived.

Term: Pedigree analysis
Definition: A diagram used to track the inheritance of traits across generations in a family.

Term: Phenotype
Definition: The observable physical or biochemical characteristics of an organism, determined by both genetics and the environment.

Term: Phenotype-wide association study (PheWAS)
Definition: A study that investigates the association between a genetic variant and multiple phenotypes across a population.

Term: Phenotypic plasticity
Definition: The ability of an organism to change its phenotype in response to environmental conditions.

Term: Pleiotropy
Definition: When a single gene affects multiple, seemingly unrelated traits.

Term: Polygenic inheritance
Definition: Inheritance of a trait that is controlled by multiple genes, each contributing a small effect.

Term: Principle of independent assortment
Definition: Mendel's law stating that the alleles of different genes are distributed independently of one another during gamete formation.

Term: Principle of segregation
Definition: Mendel's law stating that the two alleles for a gene segregate during gamete formation and are reunited at fertilization.

Term: Punnett square
Definition: A diagram used to predict the outcome of a genetic cross by considering all possible combinations of alleles.

Term: Recessive
Definition: An allele whose effects are masked by a dominant allele in a heterozygous organism.

Term: Recessive pedigree
Definition: A pedigree in which a recessive trait may skip generations and reappear when two carriers have offspring.

Term: Rule of addition
Definition: The probability rule used to calculate the likelihood of one event or another occurring (when events are mutually exclusive).

Term: Rule of multiplication
Definition: The probability rule used to calculate the likelihood of two independent events occurring together.

Term: Second filial (F2) generation
Definition: The offspring of the F1 generation in a genetic cross.

Term: Sex chromosomes
Definition: Chromosomes that determine the sex of an organism (e.g., X and Y chromosomes in humans).

Term: Self-fertilize
Definition: When an organism fertilizes itself, commonly seen in plants.

Term: Sex-linked (X-linked) inheritance
Definition: The pattern of inheritance for genes located on the X chromosome, which often results in different traits being expressed in males and females.

Term: Short tandem repeats (STR)
Definition: Short sequences of DNA that are repeated in a row and vary in length between individuals, often used in genetic profiling.

Term: Single-nucleotide polymorphisms (SNPs)
Definition: Variations at a single nucleotide position in the DNA sequence among individuals.

Term: Testcross
Definition: A cross between an individual with a dominant phenotype but unknown genotype and a homozygous recessive individual to determine the unknown genotype.

Term: Trisomy
Definition: A condition where an individual has an extra copy of a chromosome, resulting in three copies instead of the typical two.

Term: Three-point testcross
Definition: A genetic cross involving three genes to map their relative positions on a chromosome.

Term: True-breeding
Definition: Organisms that, when self-fertilized, produce offspring with the same traits over many generations.

Term: X inactivation
Definition: The process by which one of the two X chromosomes in female mammals is randomly inactivated to prevent overexpression of X-linked genes.