How Genes and Genomes Evolve

Vocabulary flashcards covering how genes and genomes evolve, including mechanisms of genetic variation, gene families, mobile genetic elements, viruses, and aspects of the human genome.

Germ line

In sexually reproducing organisms, changes to this genetic information are passed on to progeny.

Point mutations

Caused by failures of the normal mechanisms for copying and repairing DNA.

Mutation within regulatory DNA sequences

A mechanism that can change the regulation of a gene.

Gene duplication and divergence

Allows one gene to give rise to a whole family of genes, each with specialized function within a single genome.

Exon shuffling

A mechanism for the evolution of new genes in which coding sequences from different genes are brought together to make a new gene.

Mobile genetic elements (transposons)

Short segments of DNA that can move from one chromosomal location to another, potentially altering where a gene is expressed or disrupting its activity.

Horizontal gene transfer

A process by which DNA is passed from the genome of one organism to that of another, even to other species.

Somatic cell mutation

A mutation in the individual's somatic cells that does not affect the offspring.

Globin gene family

Produced by duplication and divergence from an ancestral globin gene, leading to various types like α- and β-globin.

Pseudogenes

Duplicated DNA sequences within gene clusters that are not functional.

Whole-genome duplications

Events that have shaped the evolutionary history of many species.

Homologous genes

Genes that are similar in nucleotide sequence due to common ancestry.

Noncoding DNA

Segments of DNA more likely to accumulate mutations.

Phylogenetic trees

Diagrams that depict the evolutionary relationships among a group of organisms.

Conserved synteny

The preservation of gene order in the genomes of different species.

Purifying selection

Preserves specific nucleotide sequences in a population by eliminating individuals carrying a deleterious mutation.

Pufferfish genome

Approximately 1/10 the size of mammalian genomes due to small introns and a lack of repetitive DNA.

Transposase

A specialized enzyme encoded by mobile genetic elements that mediates their movement (transposition).

Retrotransposons

Mobile genetic elements that move by first being transcribed into RNA that is reconverted to DNA by reverse transcriptase and inserted elsewhere in the chromosome.

Line-1 (L1)

A retrotransposon that comprises 15% of the human genome.

Alu sequence

A retrotransposon that makes up 10% of the human genome.

Viruses

Particles of RNA or DNA enclosed in a protein coat that are capable of replicating within a host cell.

SARS-CoV-2

A single-stranded RNA virus that caused the COVID-19 pandemic.

RNA-dependent RNA polymerase

An enzyme translated from the SARS-CoV-2 viral genome that immediately works to replicate the viral genome in a host cell.

Retroviruses

RNA-containing viruses that replicate in a cell by first making a double-stranded DNA intermediate that becomes integrated into the cell’s chromosome.

Human Genome Project

The international research effort that sequenced the first human genome.

Open reading frames (ORFs)

Sequences searched for by computer programs to identify protein-coding genes, typically >100 amino acids, starting with an initiation codon and ending with a termination codon.

RNA-Seq

A method used to determine nucleotide sequences by analyzing the RNA produced by cells.

Neanderthal genome

The first sequence completed in 2010, revealing genomic regions that have undergone changes in modern humans and indicating shared ancestry.

Single nucleotide polymorphisms (SNPs)

A form of genetic variation where a nucleotide is found at a particular position in the genome.