2. What is genetics?
The study of heredity
The passing of characteristics from parents to offspring
Traits
3. Gregor Mendel…
The first person to predict successfully how traits are
transferred from one generation to the next.
He experimented with garden pea plants.
4. Gametes?
Male and female sex cells.
When these two join through fertilization, a zygote is produced.
6. A discovery…
Mendel, experimenting with the pea plants, discovered that every
organism has two genes that control the outcome of a trait.
Tt = tall tt = short
* each gene is represented by a letter
7. AllelesGenes exist in different forms…
Allele 1 Allele 2 Trait Allele 1 Allele 2 Trait
T t = tall t t = short
8. Dominant or Recessive?
• Even though for each trait there are two alleles, only one of them actually shows…
The trait that we can observe Dominant
The trait that disappears Recessive
9. An example with plants…
If a plant has a combination… in which T is tall and t is short…
The plant will be tall… T is the dominant allele (tall)
t is the recessive allele (short)
10. Phenotype vs. Genotype
The difference is simple…
A phenotype is the way an organism looks and behaves.
A genotype is the allele combination an organism has.
11. The law of segregation
“Every individual has two alleles of each gene, and when gametes are
produced, each gamete recieves one of these alleles”
or
Individual gamete Individual gamete
12. Homozygous or Heterozygous?
The alleles don’t always have to be different…
When the alleles for a trait are the same (TT) (tt) HOMOZYGOUS
When the alleles for a trait are the different (Tt) HETEROZYGOUS
