Genetics Vocabulary Terms
Intro to Genetics
&
Mendel
Genetics
The study of how traits are passed from
generation to generation
Gregor Mendel
The “Father of Genetics.”
Trait
A characteristic (physical, personality,
medical)
When the offspring always looks
like parent
True Breeding
Hybrid
Looks like a mix of two parents when
they are cross-pollinated
Dominant
Trait is one that can hide a recessive
trait (indicated by capital letter)
Recessive
Trait can be hidden by a dominant
trait (indicated by a lower case letter)
Gene
Part of a chromosome and codes for a
trait
Allele
Segregation
Gametes
A different version of a gene
The process of separating alleles
The sex cells (egg & sperm)
Genetics Vocabulary Terms
PROBABILITY VOCABULARY
Probability
Punnett Square
The chance of something happening
Penny: Heads or Tails
50% or 1/2
A tool used to figure out possible
outcomes
Homozygous
When both alleles look the same
(AA or aa)
Heterozygous
When both alleles do not look the
same (Aa)
Phenotype
The “physical appearance”
(Ex: Brown Hair, Tall, Short,
Wrinkled, Round)
Genotype
The “gene type” or allele letters
(Ex: TT, Tt, tt)
Genetics Vocabulary Terms
Gene Expression
Independent Assortment
How one trait that is expressed
does not affect the other
(Ex: hair color and eye color)
Incomplete Dominance
When there is a blending of traits
and a totally new trait is observed
(ex: Red flowers x White flowers
= Pink flowers)
Co-Dominance
When both alleles are expressed
equally and one does not dominate
over the other (ex: Blood types
AB)
Multiple Alleles
When more than the usual 2 alleles are
present (ex: IA IB i)
Polygenic Traits
Many genes working together
giving wide variety of outcomes
(ex: height, skin color, hair color)
Genetics Vocabulary Terms
Meiosis
Homologous Chromosomes
Diploid
Matching set of two chromosomes
(A pair of chromosomes on a
karyotype)
Having 2 of every kind of
chromosome
(2N)
Haploid
Having only 1 chromosome
(half or 1N)
Meiosis
Process of making gametes
(sex cells)
Tetrad
Crossing Over
When 2 pairs of chromatids
are together during meiosis
When tetrads cross and exchange
genes providing diversity
Genetics Vocabulary Terms
Human
Heredity
Human Heredity
Karyotype
Sex Chromosome
Autosomes
Focusing on human traits
A picture of all chromosomes matched
up and helps to show abnormalities
The 23rd pair of chromosomes
and determines gender
XX=Female XY=Male
All the other 22 pairs of
chromosomes other than sex
chromosomes
Sex-Linked Traits
Sex-linked gene/trait
Non-disjunction
Traits that are linked to the
sex chromosomes such as
hemophilia and colorblindness
When chromosome pairs do
not separate during
Anaphase I