1. Terms you’ve gotta know
BASIC GENETICS TERMS
Terms you’ve gotta know

2. GENE
A section of DNA that has information about a specific trait of an organism
A chromosome is a chunk of DNA and genes are parts of chromosomes

3. ALLELE Each form of a gene OR each option for each gene
Example: attached or unattached earlobes are the alleles for the gene for earlobe shape

4. DOMINANT/RECESSIVE
Dominant: a genetic factor that blocks another genetic factor
Recessive: a genetic factor that is hidden by the presence of a dominant factor
Question: Using pea plants, how did Mendel figure out that genes are either dominant or recessive?

5. HOMOZYGOUS/HETEROZYGOUS
Homozygous: two alleles for a gene that are the SAME
Heterozygous: two alleles for a gene that are DIFFERENT
You get one allele from your mom and one from your dad.
If you get the same from your mom and dad, you are homozygous for that trait.
If your mom gave you a different allele than your dad, you are heterozygous for that trait

6. GENOTYPE Tt
Alleles that make up an organism. Your genotype is which genes you have!
Genotype is written in letters
It is usually the first letter of the dominant trait to make it easier
Choose a letter for each of these traits. Write both the dominant and the recessive genotype allele letters
Free Earlobes
Freckles
Dimples
Tongue-roller

7. GENOTYPE
Now, using your letters from before write a genotype for a person without freckles
Write a genotype for a person with freckles

8. GENOTYPE-HETEROZYGOUS AND HOMOZYGOUS
A Heterozygous genotype means an organism has both the dominant and the recessive allele
Homozygous recessive means an organism has 2 recessive alleles
Homozygous dominant means an organism has 2 dominant alleles
Write a heterozygous genotype for handedness
Write a homozygous dominant and a homozygous recessive genotype for handedness

9. PHENOTYPE Observable traits and all characteristics of an organism
What you look like (your phenotype) is based on what your genotype is (your genes)
What will the phenotype of these genotypes be:
PP, Pp, pp (Dominant is purple flowers, recessive is white flowers)
RR, Rr, rr (Round peas are dominant to wrinkled peas)
YY, Yy, yy (Yellow peas are dominant to green peas)

10. GENOTYPE/PHENOTYPE PRACTICE
What is the genotype for white flowers?
What are the genotypes for purple flowers?
What phenotypes will result from these genotype: PP, Pp, pp
You’ve got it!! Now you are a genetics super star 