Genetics and Evolution Review

Vocabulary flashcards covering key concepts from lectures on Mitosis, Meiosis, Mendelian Genetics, Extensions of Mendelian Inheritance, Hardy-Weinberg Equilibrium, and Evolution in Real Populations.

Mitosis

A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus.

Meiosis

A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes.

Gamete

A mature haploid male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote.

Homologous chromosomes

A pair of chromosomes (one inherited from each parent) that are similar in length, gene position, and centromere location.

Recombinant chromosomes

Chromosomes that have undergone crossing over during meiosis, resulting in a combination of alleles from both parents.

Law of segregation

States that during the formation of gametes, the two alleles for a heritable character separate (segregate) from each other such that each gamete carries only one allele for each character.

Law of independent assortment

States that the alleles for different genes assort independently of one another during gamete formation, assuming they are on different chromosomes or far apart on the same chromosome.

Crossing over

The exchange of genetic material between homologous chromosomes during prophase I of meiosis, generating diversity in gametes.

Particulate inheritance

The concept that hereditary traits are passed from parents to offspring as discrete, unchangeable units (genes).

Monohybrid cross

A genetic cross between parents that differ in a single trait.

Parental generation (P)

The first set of parents in a genetic cross.

F1 generation

The first filial generation, consisting of the offspring from the parental (P) cross.

F2 generation

The second filial generation, consisting of the offspring from a cross between two F1 individuals.

Test cross

A genetic cross between an individual with an unknown genotype expressing the dominant phenotype and a homozygous recessive individual, used to determine the unknown genotype.

Dihybrid cross

A genetic cross between parents that differ in two traits.

Trihybrid cross

A genetic cross between parents that differ in three traits.

Pedigree

A chart documenting the phenotypes and genotypes of a family's members across generations, used to track genetic traits.

Incomplete dominance

A form of intermediate inheritance in which one allele for a specific trait is not entirely dominant over the other allele, resulting in a blended phenotype in heterozygotes.

Codominance

A form of inheritance in which both alleles for a gene are fully and equally expressed in the heterozygote, resulting in a phenotype that shows both traits distinctly.

Heterozygote advantage

The case in which a heterozygous individual has a higher fitness than either homozygous individual.

Pleiotropy

A genetic phenomenon in which a single gene affects multiple, seemingly unrelated phenotypic traits.

Epistasis

A phenomenon where the expression of one gene is affected by another gene (modifier gene) at a different locus.

Genetic linkage

The tendency of genes or alleles that are located close together on a chromosome to be inherited together during meiosis.

Recombination rate

The frequency with which crossing over occurs between two linked genes, expressed as the number of recombinant offspring divided by the total number of offspring, and indicative of the distance between genes.

X-linked traits

Traits determined by genes located on the X chromosome, often resulting in males being more likely to express recessive phenotypes due to having only one X chromosome.

Complex traits

Traits that are influenced by multiple genes and often also by environmental factors.

Phenotypic plasticity

The ability of an organism to change its phenotype in response to changes in the environment.

Hardy-Weinberg (HW) theorem/model

A model describing a non-evolving population where allele and genotype frequencies remain constant across generations if five specific conditions are met.

Hardy-Weinberg conditions

No mutation, random mating, no natural selection, extremely large population size, and no gene flow.

Allele frequencies

The relative proportion of a specific allele in a population, represented by p and q in the Hardy-Weinberg equation (p+q=1).

Genotype frequencies

The relative proportion of specific genotypes in a population, represented by p^2, 2pq, and q^2 in the Hardy-Weinberg equation (p^2+2pq+q^2=1).

Multiplication rule of probability

States that the probability of two or more independent events occurring together is the product of their individual probabilities.

Natural selection

A mechanism of evolution where individuals with advantageous traits in a particular environment are more likely to survive and reproduce, passing those traits to their offspring.