Review for Statistical Genetics

STA2080 Knowledge Prerequisites

Human Genome

All biological material transmitted from parents to offsprings; determines inherited characteristics

Chromosomes

Carries DNA and genetic information, contains biological material and exists in pairs of 23 in the human genome itself.

Autosomal Chromosome Pairs / Autosomes

Describes 22 of the 23 chromosome pairs; where two chromosomes in a pair are very similar / homologous but not identical to each other

Sex Chromosome

23rd pair of chromosomes that are non-identical: Females have two non-identical X chromosomes (XX) whereas males are XY

Centromere of Chromosome

Region near the middle of the chromosome contributing to cell division and reproduction; divides each chromosome into short arm p and long arm q

DeoxyriboNucleic Acid (DNA)

Building block of chromosomes; each chromosome is composed of long strands of DNA

Biological material of inheritance; determines how proteins are manufactured in the body.

Double Helix structure: Complementary base pairs (A C T G) where the former two and latter two are always paired with each other

Genes

Section of DNA which instructs cell to create certain proteins; about 20,000 - 30,000 genes distributed throughout genome

Vary significantly in size: Small genes contain few thousand base pairs, large ones contain up to millions

Exons

Parts of gene that code for proteins; < 2% of all DNA

Introns

Parts of gene that do not code for protein but plays more of a regulatory role

Genetic Locus

Particular location in a chromosome that is polymorphic (i.e. Data at said locus can have, but not necessarily have multiple variants)

Polymorphism

Genetic locus describing polymorphic location on chromosome, but data specifically has multiple variants

Alleles

Different variants at a polymorphism

Aside: When only two variants exist, convention refers them as “A” and “a”

Homozygous

Two identical copies of a gene variant inherited from parents (AA or aa)

Heterozygous

Inheriting a different gene variant from each parent (Aa)

Genotype

Pair of alleles at a location (AA, Aa, aa)