Brianna Smith

What is the study of Genetics?

Genetics is a branch of biology that studies heredity.

Who discovered genetics?

The person who discovered genetics was monk in Austria by the name of Gregor Mendel. He studied this through pea plants in order to display genetic discoveries.

Important Terms!

Dominant: The Allele in a genotype that overpowers the recessive; the uppercase letter.Recessive: The Allele in a genotype that is overpowered by the dominant, but can appear in a homozygous recessive genotype; the lowercase letter.Heterozygous: A pair of alleles in a genotype that have one dominant and one recessive allele displayed. ex: TtHomozygous: A pair of alleles in a genotype that have two of the same allele (Dominant or Recessive). ex: TT or ttGenotype: Gene combinations of a organism; can be homozygous or heterozygous. ex: Tt, TT, ttPhenotype: The physical appearance and the behavior of an organism in accordance with their genotype. ex: green

Incomplete Dominance!

Incomplete dominance is when the phenotype of heterozygous individuals is intermediate between those of the 2 homozygotes. This means that no trait dominantes over the other but instead combines to create a new phenotype. EX: A red and white flower pro create but instead of there being a split of red and white flowered offspring, their offspring will be pink. This is incomplete dominance.


Codominance is when the phenotypes of both homozygotes produced in heterozygous individuals is displayed equally. So in this case a red and white flower cross but instead of making a pink flower, they make a flower with splotches of red and white, thus equally expressing  the alleles of each homozygote.

Multiple Alleles!

Multiple alleles are an inheritance pattern in which traits are contolled by more than two alleles. They are used to determine blood type. EX: Type A blood can represented by iAi or iAiA. Type B can be represented by iBi or iBiB. Type AB can be represented by iAiB and type O can be represented by ii. These also help determine what blood types can recieve blood transfusions from other blood types.

Sex-Linked Traits!

These are characteristics determined by genes on sex chromosomes. Sex-linked traits can be on the X or the Y chromosome, but the most common chromosome isx the X. The alleles are written as subscripts for X and Y sex-linked traits. They look like XRXr or XrY.Examples of sex-linked traits would be colorblindness. The carrier would be the mother. If she has colorblindness or is a carrier, her son will always be colorblind because she provides the X chromosome while her husband provides the Y. If her daughter receives an X chromosome with a CB allele, and her father is CB she will be as well. If her father isn't she will only be a carrier.