M5 definitions

Gene Pool

the sum of all different types of genes and alleles in a population

Genetic Diversity

the number and frequency of different alleles of all genes

Genetic Variability

the tendency of individuals to have different genetic characteristics (alleles)

Polymorphism

the occurrence of 2 or more forms of a particular gene/phenotype

Single-Nucleotide Polymorphism (SNP)

mutations replacing one base with another (point-mutation)

Genetic Markers

an identified DNA sequence at a specific chromosome locus

Genome-Wide Associated Studies (GWAS)

compares the genomes of multiple affected individuals (~25-50) with healthy/unaffected individuals, aims to find SNP w/ higher frequency in infected individuals

Haplotype

a group of SNPs associated with a trait (usually disease)

Sex-linkage

genes carried on sex (X, Y) chromosomes which encode for characteristics beyond biological sex

Carrier

an individual who carries one allele for a trait, but does not express it in their phenotype

Often females (XX) for recessive sex-linked traits

Incomplete Dominance

both alleles present within a heterozygous individual’s phenotype → intermediate or new phenotype different from either parent

Multi-allelic Traits

phenotypic traits w/ multiple alleles within the population

Polygenic Traits

phenotypic traits encoded by multiple genes w/ unique alleles

Continuous Variation

many genes encode for trait → various phenotypes

Discontinuous Variation

one gene encodes for trait → distinct alleles

Autosomal Recessive Inheritance

genes found on non-sex (autosomal) chromosomes w/ dominant + recessive allele

1st Law of Dominance & Segregation

during gamete formation, a pair of alleles for one trait (gene) separates into two gametes

2nd Law of Independent Assortment

alleles on homologous chromosomes segregate independently of other chromosomes

Mendel’s 1st Experiment

pure-breeding cross of homozygous dominant (TT) and homozygous recessive (tt)

Mendel’s 2nd Experiment

monohybrid cross of first F1 Generation

Allele

alternate forms of a gene (e.g hair colour); found @ same locus on homologous chromosome

Genotype

cell’s genetic makeup, comprised of 2 alleles (mother’s, father’s)

Diploid

individuals w/ two alleles of each gene

Haploid

cells (gametes ) w/ only one allele of each gene

Phenotype

physical expression of an individual’s traits/characteristics (appearance)

Homozygous

‘pure-bred’; genotype w/ identical alleles

Heterozygous

‘hybrid’; genotype w/ diff. alleles

Homologous chromosomes

chromosomes which code for the same genes but different information

Chromatid

one of the two strands which comprise a chromosome

Chiasma

where chromosomes meet during crossing over

Loci

position of exchanged genes, which remains identical during crossing over

Biological fitness

reproductive success of an individual, selected by environmental + selection pressures

Reproduction

making more of the same organism

Species

a group of organisms that can reproduce + produce fertile offspring

Reproductive success

ability of an organism to have offspring that survive to reproduce, i.e. the number of offspring who have offspring