1. Genetics and Heredity
Passing on traits from parent to offspring is heredity!
What are some traits that you got from your parents?

2. Gregor Mendel Circa. 1850’s

3. Mendel’s Success Pea plants grew quickly and were inexpensive
Mendel realized that pea plants had different traits for example: Tall vs. Short
Mendel repeated his experiments many thousands of times and calculated data.

4. Be mendel and plant peas!

5. Dominant Traits
In pea plants Purple flowers were dominant. So a purple parent crossed with a white parent always resulted in 100% purple.
WW x ww = Ww.
Dominant traits are symbolized by uppercase letters: WW= dominant purple.

6. Recessive Traits
Recessive traits are symbolized by little letters ww= recessive (white).
? So if you had a plant with the genotype Ww what color would it be according to the law of dominance?
Purple!

7. Gene Segregation….what does segregation mean?
Mendel thought that genes had two genes for each trait (one from mom one from dad)
These genes were then symbolized by letters. WW= dominant purple and ww = recessive.
These genes separate in the formation of gametes. (so your parent can only give you 1 gene)
WW x ww = Ww.

8. Punnett Squares
The punnett square is a visual aid to help in calculating ratios of genetic probability.
Insert Alleles

9. Terminology (the study of terms)
Allele- each alternative form of a gene: either W or w
Genotype- the combination of genes: Ww
Phenotype-the appearance of that trait: Purple
Homozygous-two alleles are the same WW or ww
Heterozygous- two alleles are different: Ww

10. The genotype codes for the phenotype

11. What is the mother’s Genotype? What is the first child’s genotype?
What is the father’s Phenotype?
Which fish are homozygous and which ones are heterozygous?

12. Two Traits
Boxhead

13. Probability Calculation
A coin has two sides what is the probability of flipping it and ending up tails?
What is the probability of it being tails 3x in a row?
A die has 6 sides what is the probability of a two being rolled?

14. Incomplete Dominance
The four o’clock exhibits incomplete dominance…both genes are expressed equally. RR x R’R’ the apostrophe is known as “prime”
Say R prime

15. Sex Determination (the easiest cross ever!)
Women have XX chromosomes and men have XY chromosomes.
XX x XY