Evolution of Genes and Genomes: Molecular Evolution

A series of vocabulary flashcards based on the concepts covered in the lecture about molecular evolution, key terms, and definitions within the context of genes and genomes.

Genome

The complete set of all genetic material within an organism, including all of its genes, noncoding regions of DNA or RNA, and mitochondrial and chloroplast DNA (if applicable). It encompasses all the hereditary information required to build and maintain that organism.

Mutation

A spontaneous and random change in the DNA sequence that occurs during DNA replication or due to environmental factors. Mutations introduce new genetic variation and serve as the essential raw material upon which evolutionary processes, such as natural selection, act.

Point Mutation

A specific type of mutation involving the alteration of a single nucleotide (the basic building block of DNA) within a DNA sequence. This change can involve a substitution, insertion, or deletion of a single base.

Synonymous Substitution

A specific type of point mutation where a nucleotide substitution occurs, but due to the redundancy of the genetic code, the changed codon still codes for the same amino acid. This type of mutation is often referred to as a 'silent mutation' because it typically does not affect the structure or functioning of the resulting protein.

Nonsynonymous Substitution

A specific type of point mutation where a nucleotide substitution results in a codon that codes for a different amino acid. This change in amino acid can potentially alter the protein's structure, stability, or function, leading to a functional change in the gene.

Transposable Elements

Segments of DNA that possess the ability to move from one location to another within the genome, often referred to as 'jumping genes.' These elements can cause mutations, alter gene expression, and contribute to genomic rearrangement and evolution.

Lateral Gene Transfer

Also known as horizontal gene transfer, this is the non-sexual movement of genetic material (genes, organelles, or fragments of genomes) from one organism or lineage to another. This process is common in bacteria and archaea, enabling rapid adaptation and spread of traits like antibiotic resistance.

Hox Genes

A highly conserved group of regulatory genes that play a critical role in controlling the development of the basic body plan and the proper segmentation of structures along the anterior-posterior axis in animal embryos. They encode transcription factors that switch on other genes.

Epigenetic Gene Regulation

Changes in gene expression that do not involve altering the underlying DNA sequence itself, but rather through modifications to chromatin structure (e.g., DNA methylation, histone modification) that impact how genes are read. These modifications can be heritable across cell divisions and even generations.

Gene Duplication

An evolutionary event where an entire gene, or a segment of DNA containing a gene, is copied, resulting in two copies of the gene within the genome. One copy can retain its original function while the other can be free to evolve new functions, become a pseudogene, or be lost.

Allele

One of two or more alternative forms of a gene that arise from mutation and are found at the same place (locus) on a chromosome. For example, a gene for eye color might have alleles for blue or brown eyes.

Genotype

The specific genetic makeup of an individual organism, referring to the set of alleles it possesses for a particular gene or set of genes. It represents the inherited genetic constitution that, together with environmental factors, determines an organism's phenotype.

Phenotype

The observable characteristics or traits of an organism, which are the result of the interaction between its genotype (genetic makeup) and environmental influences. Examples include physical traits like height and eye color, as well as biochemical, physiological, and behavioral traits.

Genetic Drift

A mechanism of evolution characterized by random fluctuations in allele frequencies from one generation to the next, entirely due to chance events. Its effects are more pronounced in smaller populations, where random events can cause significant changes in genetic variation, independent of natural selection.

Gene Flow

The transfer of genetic material (alleles or genes) from one population to another, typically through the migration of individuals or gametes and subsequent interbreeding. Gene flow can introduce new alleles into a population, increase genetic variation, and make populations more genetically similar to each other.