SAC bio unit 2 aos 1

Karyotype

A visual representation of the chromosomes from a cell nucleus of any individual, therefore a full set of the species chromosomes

Autosome

Refers to the 22 chromosome pairs in humans that determine body traits such as height,

Sex chromosomes

Whilst humans have 1 pair of sex chromosomes called X and Y, determining if someone is male or female

Epigenetic factors

Changes in gene expression caused by modification of DNA without changing the sequence

DNA methylation

The process of adding methyl group to C bases of DNA

Histone modification

The addition of chemical groups to histone proteins which affects the spacing between nucleosomes

Genotype vs phenotype

The particular genetic makeup and allele for each gene, whilst phenotype is the visible expression of each gene

Test cross

With a homozygous recessive phenotype to determine the genotype of the dominant individual

Co dominance

Two traits are equally dominant, a heterozygous displays both traits

Incomplete dominance

Heterozygous displays an intermediate phenotype that is a combination of both alleles