Bio Lecture 19/20 Mendel

Trait

a characteristic or feature of an organism, often one that can be inherited

Hybridization

the process of breeding organisms from different varieties, breeds, or even species to produce hybrid offspring

P generation

Parental generation in a cross

F1 generation

first generation of offspring, from p generation

F2 generation

second generation of offspring, from F1 generation

monohybrid

a breeding experiment focused on the inheritance of a single trait controlled by one gene, where BOTH parents are heterozygous for that trait

dihybrid cross / trihybrid cross

a cross between two individuals identically heterozygous at two (di) or three (tri) genes, for example AaBb x AaBb (di) or AbBbCc x AbBbCc

allele

a variant form of a gene, representing one of two or more possible sequences at a specific location (locus) on a chromosome

locus

the specific, fixed position of a gene or genetic marker on a chromosome

dominant allele

a version of a gene that determines the phenotype (observable trait) of an organism when present, even if the individual also has a different, recessive allele

recessive allele

a version of a gene that only expresses its trait when two copies are present, one from each parent

Mendel’s law of segregation

the two alleles segregate (separate from each other) and end up in different gametes: only one of a pair of alleles is passed to a gamete

Mendel’s law of independent assortment

Each pair of alleles segregates independently of each other pair of alleles during gamete formation

genotype

An organism’s genetic makeup

phenotype

An organism’s outward appearance

homozygous

having a pair of identical allele

heterozygous

having a pair of two different alleles