Genetic Terminology
 Trait - any characteristic that can be
passed from parent to offspring

 Heredity - passing of traits from parent
to offspring
 Genetics - study of heredity
 Gene – A segment of DNA that codes
for a trait (protein)
More Terminology
 Dominant - stronger of two genes expressed in
the hybrid; represented by a capital letter (T or R
or Y)
 Recessive - gene that shows up less often in a
cross; represented by a lowercase letter (t or r or
y)
 Alleles - two forms of a gene (dominant &
recessive)
Vocabulary
 Genotype: The genetic makeup of an individual
for a trait - not the observable or detectable
characteristics.
 The make up of the alleles in a gene pair
 Examples B=Brown eyes b = blue eyes
 Bb (brown) BB (brown) bb (blue)
 Phenotype: The observable or detectable
characteristics of an individual organism; the
detectable expression of a genotype.
 Brown eyes, blue eyes
Vocabulary
 Purebred: Offspring that are the result of mating
between genetically similar kinds of parents--the
opposite of hybrid.
 Allele pair is either both dominant - BB or both recessive
- bb
 Hybrid: Offspring that are the result of mating
between two genetically different kinds of parents--the
opposite of purebred.
 Allele pair is a mix of a dominant and a recessive allele -
Bb
Vocabulary
 homozygous genotype: A genotype consisting of two
identical alleles of a gene for a particular trait. (both
dominant or both recessive) BB or bb
 heterozygous genotype: A genotype consisting of
two different alleles of a gene for a particular trait. Bb
(dominant and recessive allele)
 Punnett squares are a way to look at the gene pairs an
offspring will inherit from their parents. It shows the
probability of each match.