genotype to phenotype — codon

haploid number

• the number of different types of chromosome

• symbolized with an n

ploidy

• number of copies of each type of chromosome

• haploid: one of each type of chromosome

• placed before n

homologous chromosomes (homologs)

• same type of chromosome

• contain the same genes, but potentially different alleles

mutation

• any change in the base sequence of RNA

• occur at random

• change the genotype, specifically, they create new alleles

• may change the phenotype if it changes the RNAs and proteins that get produced

what do recessive alleles often produce

proteins that are broken, inactive, or missing

sex-determination systems

• one chromosome in each haploid set is associated with the sex

• X and Y are called sex chromosomes, other 22 are called autosomes

• XX are females

• XY are males (“why would a man be there”)

polygenic traits

• traits that show continuous variation

• influenced by the products of many genes instead of just one

why are polygenic traits so hard to study

controlled by many genes with small effects and are strongly influenced by the environment