Unit 1

Locus

location in the genome

can mean genomic region, specific nucleotide, or anything in between

Polymorphism

occurrence of two or more alleles at a locus in a population

does not need to be a gene or do anything functional, just needs to differ among people

Allele

any of the variant forms of genetic material at a polymorphism

Genotype

the combination of two alleles for a polymorphism in a person

Phenotype

trait

observable manifestation of a genotype

Homozygous

having two copies of the same allele at a locus

Heterozygous

having copes of two different alleles at a locus

Minor Allele

the less common allele at a biallelic locus

Major Allele

the more/most common allele at a locus

Dominant/Recessive

describes the effect of an allele on a phenotype

Affected

a person who manifests a genetic condition

Carrier

a person who has a risk allele, but not the genetic condition itself

Central Dogma

DNA is transcribed to mRNA, which is translated to protein

DNA holds the information for coding proteins

Gene

unit of inheritance

sequence of nucleotides forming promoter, exons, and introns, that ultimately codes a polypeptide or nucleic acid molecule

Genetic Code

three-nucleotide codons code for specific amino acids

Genetic Sequence

the sequence of nucleotides in a genome or locus

Inheritance

offspring inherit one copy of the genome from each parent

Unilineal Relatives

related through only one parent

examples: cousins, parent/offspring, grandparent/grandchild, avuncular, half-siblings, half-avuncular

Bilineal Relatives

related through both parents

examples: siblings, double cousins, inbreeding loop

Identical-By-Descent (IBD)

two alleles inherited by a common ancestor

two alleles can be in the same person or in different people

common ancestor depends on how far back you look

Autozygous

two alleles inherited from the same ancestor in the same person

identical-by-descent and homozygous

Identical-By-State (IBS)

two of the same allele not inherited by a common ancestor

Coefficient of Kinship

probability that two randomly chosen alleles in two different people are identical-by-descent

average expected percentage identical-by-descent across the entire genome

measure of how closely related two people are