Module 3 - Population Genetics & Evolution

Oncogene

A mutated gene that in certain circumstances can promote cancer cell growth. Oncogenes are typically involved in cell signaling pathways and control cell division.

Proto-oncogene

A normal gene that can become an oncogene due to mutations or increased expression, typically involved in regulating cell growth and differentiation.

Reverse Transcriptase

Uses single-stranded RNA as template to synthesize DNA, reversing flow of information in a cell by catalyzing the transcription of RNA into complementary DNA (cDNA).

Polymorphism

The occurrence of two or more variations of a particular gene in a population, contributing to genetic diversity and evolution.

Genetic Drift

the random change in the frequency of an existing gene variant in a population due to random chance

Gene Flow

Movement of alleles from one population to another through interbreeding between members of each population which can increase genetic diversity and affect allele frequencies.

Genotype Frequency

Proportion of a specified genotype among all the genotypes for a particular gene or set of genes in a population

Allele Frequency

Proportion of a specified allele among all the alleles of a gene in a population

Hardy-Weinberg Equilibrium

A state in which allele and genotype frequencies do not change over time, implying absence of evolutionary forces

Founder Effect

Genetic drift that occurs when only a few individuals establish a new population

Natural Selection

The process by which certain traits increase in frequency within a population due to improved survival and reproduction rates of individuals with those traits.

Directional Selection

A mode of natural selection in which an extreme phenotype is favored over other phenotypes, causing a shift in the population's trait distribution.

Stabilizing Selection

A mode of natural selection that favors intermediate phenotypes, reducing variation and maintaining the status quo in a population's traits.

Disruptive Selection

A mode of natural selection that favors extreme phenotypes at both ends of the spectrum over intermediate phenotypes, leading to increased variation within a population.

Coevolution

The process by which two or more species influence each other's evolution, often through interactions such as predation, competition, or mutualism.

Fitness

The ability of an organism to survive and reproduce in its environment, often measured by the number of offspring produced.

Species

A group of organisms that can interbreed and produce fertile offspring, sharing common characteristics and genetic similarity.

Speciation

The formation of new and distinct species in the course of evolution

Allopatric Speciation

The process of speciation that occurs when populations are geographically separated, leading to reproductive isolation and the evolution of new species.

Peripatric Speciation

A form of speciation that occurs when a small population becomes isolated at the edge of a larger population's range, leading to genetic divergence.

Sympatric Speciation

The evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region

Morphospecies Concept

The idea that members of the same species usually look like each other more than other species

Ecological Species

The concept that there is a one-to-one correspondence between species and its niche

Evolutionary Species

A group of populations that shares a common evolutionary fate through time

Ancestral Character

A trait or feature that was present in the ancestor of a group of species and is passed down to its descendants.

Derived Character

A trait that has evolved in a lineage, distinguishing it from ancestral traits, and is often used to define evolutionary relationships.

Parallel Evolution

The independent evolution of similar traits in different species due to adaptation to similar environments or ecological niches.

Homologous Character

A trait that is shared by two or more species due to their common ancestry, often reflecting evolutionary relationships.

Paraphyletic Lineage

A group of organisms that includes some, but not all, descendants of a common ancestor, resulting in a lineage that does not form a complete clade.

Monophyletic Group

A group of organisms that includes all the descendants of a common ancestor, forming a complete clade.

Polyphyletic Group

A group of organisms that includes descendants from multiple ancestors, resulting in a lineage that does not reflect true evolutionary relationships.

Analogous Character

A trait that has evolved independently in different species, often due to similar environmental pressures, rather than from a common ancestor.