Genetics

vocabulary 

heredity
gene
trait
allele
genotype
phenotype
homozygous
heterozygous
dominant
recessive
complete dominance
incomplete dominance
co-dominance
multiple alleles
sex-linked traits

Gregor Mendel

Known as the "Father of genetics" because of his experiments with pea plants. Mendel spent two years contacting control experiments to ensure pea plants bred true. This meant that round shaped peas produced only round shaped peas and that wrinkled peas produced only wrinkled pea offspring. after Two years of control testing Gregor decided to being his test crossing. He found that crossing a round parent with a wrinkled parent only round peas were produced, it was asif the wrinkled trait had dissapeared! He conducted further experiments including crossing the offspring and this resulted in the reappearance of the wrinkled gene, it was asif it was hidden for a generation.

He collected massive amounts of data that he used to come up with a specific formula for inheritance, He was able to uncover the fact that each individual contained 2 bits of inheritance and only passed one of them on to their offspring. the second fact he uncovered is that some traits are dominant over other traits while some are recessive.

Mendel's Laws

Law of segregation

The Law of Segregation states that every individual possesses a pair of alleles for any particular trait and that each parent passes a randomly selected allele to its offspring.

Law of Independent Assortment 

The Law of Independent Assortment states that separate genes for separate traits are passed independently of one another from parents to offspring. That is, the biological selection of a particular gene for one trait to be passed to the offspring has nothing to do with the selection of the gene for any other trait. 


Law of Dominance

Mendel's Law of Dominance states that recessive alleles will always be masked by dominant alleles. Therefore, a cross between a homozygous dominant and a homozygous recessive will always express the dominant phenotype, while still having a heterozygous genotype.

inheritance patterns

Complete dominance

Complete dominance is a form of inheritance in which the dominant trait completely masks the recessive trait in the heterozygote
Incomplete dominance 

Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely dominant over the other allele. This results in a third phenotype in which the expressed physical trait is a combination of the dominant and recessive phenotypes. (the heterozygote is a mix or blend of the two phenotypes)
Codominance

Codominance is a form of intermediate inheritance in which more than one allele for a specific trait is dominant. This results in a third phenotype in which both traits are expressed individually, not blended. (the heterozygote has BOTH traits visible)
Multiple Alleles
Sex Linked

Chromosomal mutations