genetic variation glossary 🍓🐅🌟🦒🌿🫐🦩🌷

Flashcards generated from lecture notes for exam preparation.

What is Natural Selection?

Biological process where organisms with different genes adapt, increasing their survivability in their habitat/environment.

What is Directional Selection?

Type of natural selection where one extreme inheritable trait is selected, altering the genotype and phenotype of a population.

What is Stabilising Selection?

Type of natural selection where extreme traits are selected against, decreasing gene variants and potentially reducing a population's adaptations.

What is Disruptive Selection?

Type of natural selection where extreme traits are prioritised, increasing genetic variation and forming more adaptations in a population.

What is Selection Pressure?

An environmental factor altering the frequencies of alleles in a population; organisms with suitable alleles survive and reproduce.

What is Allele Frequency?

The frequency with which a specific allele appears in a gene pool.

What is Asexual Reproduction?

Reproduction of identical offspring from a single parent, without gametes.

What is Beneficial Mutation?

Change in base DNA sequence creating a new allele helping offspring survive and giving them a competitive advantage/adaptation.

What is Fixed Allele?

An allele that is the only variant for a gene in a population; all other variations have been lost.

What is Frameshift Mutation?

Addition or removal of a base altering the reading frame gene sequence, often resulting in a completely different amino acid sequence.

What is Harmful Mutation?

Change in base sequence creating a non-functioning protein, resulting in deficiency or making survival harder.

What is Incomplete Dominance?

When one allele is not completely dominant, resulting in an intermediate phenotype in a heterozygous organism.

What is Missense Mutation?

Changes to a DNA sequence resulting in one amino acid sequence altering / changing in the gene sequence.

What is Nonsense Mutation?

Changes to a DNA sequence resulting in a premature stop codon sequence producing a protein with a reduced number of amino acids than originally in the gene sequence.

What is Point Mutation?

Changes to one base in a gene sequence, including substitution, deletion, insertion and inversion.

What is a Recombinant?

A chromosome with a combination of both maternal/paternal genetic material as a result of crossing over.

What is Meiosis?

Cell division process after fertilization when a diploid cell forms a haploid cell (four daughter cells).

What is Crossing Over?

When homologous chromosomes exchange genetic material, forming new allele combinations.

What is Independent Assortment?

When alleles of two or more gene variants are sorted into gametes independently of one another.

What is Segregation?

When pairs of gene variants (allele pairs) are separated in gamete formation, so a gene only has one allele (in a gene pair).

What is Complete Dominance?

When an allele with heterozygous condition is considered completely dominant fully masking the recessive effect & traits.

What is Founder Effect?

The loss of genetic variation in a population through establishing a new smaller population by translocation from a larger population

What are Gametic Cells?

Sex/reproductive cells (sperm and eggs) - cells with ½ the chromosome number, if a mutation is in the cells it results in forming a zygote - all cells in the offspring will have the mutation.

What is Pure Breeding?

A group of genetically identical organisms that only produce one type of gamete as the gametes are homozygous.

What is Test Cross?

A genetic cross between a homozygous recessive organism and a suspected heterozygote to define the genotype

What is Sex-Linkage?

When alleles with gene variants for a specific trait are located on the sex chromosomes a corresponding gene is located on X or Y chromosome.

What is Bottleneck effect?

A change of allele frequency following a catastrophic reduction in the size of a population.

What is Artificial Selection?

Breeding organisms with specific traits.