1. Ch. 12

2. Notes: Genetics  Mendel- The “Father of Genetics” -Used peas in experiments. -Peas are, in nature, self pollinators -Mendel was able to control the pollination by covering the flowers and removing the pollen grains.

3. Pollen Grains Pistil

4. Family Pedigree  Shows certain genetic traits passed down.

6. 1 st (TOP) line is the ______ Generation 3 rd line is the ______ Generation. 2 nd line is the _______Generation.

7. Punnett Square  Punnett Square- A chart that shows the possible genotypes of a cross. *The female goes across the top, male goes down the side.

8. Gametes  Gametes = Sex Cells =sperm / egg

9.  Haploid= (Half)=(1N)  *In Humans 1(23) = 23  *Half the normal number of chromosomes.  *Find it only in gametes.  Diploid=(Full set)=(2N)  *In Humans 2(23) = 46  *Full number of chromosomes  *Found in body cells

10.  Genotype -The actual letters for a trait. Ex. BB, Hh, kk  Phenotype -The physical appearance of a trait. Ex. Blue, Curly, Tall

11. Ex: Which is the genotype? A- White rabbit B- WW

12.  Heterozygous -Hybrid -means “different”, use a Hh (one is capital, one is lower case)  Homozygous -Purebred -means “same”, use HH or hh (Both are capital, or both are lower case.)

13. Liger- hybrid example

14. Purebred example-Arabian horse

15.  Allele -Used to describe the letters in a genotype. Ex. 2 alleles-BB  There are 2 alleles for every trait, “one comes from mom and one comes from dad”.

16. Human Chromosomes  Humans have 46 chromosomes, organized in 23 pairs.

17.  The first 22 pairs are called AUTOSOMES.  The last pair, #23, are called the SEX CHROMOSOMES. *In males it is XY and in females it is XX.

18. When female gametes form: XX Diploid ( beginning cell) X (egg)*** (3 polar bodies) *Haploid cells form and only give X’s to the offspring.

19. When male gametes form: XY Diploid (beginning cell) X Y Haploid *Haploid cells give either X or Y to the offspring.

20. Genes on the Sex Chromosomes  The genes found on the sex chromosomes are called SEX- LINKED.  Ex. Baldness in men

21.  Usually with sex linked disorders, the males express/show the disorder and the females are the carriers.

22. Example: Colorblindness -Sex linked trait -Missing certain pigments in eyes to decipher certain colors. -Most common kind is red/green colorblindness -Affects 8% males and 1% females

23. Last, but not least…  Dominant traits are written as ______ Capital letters, always written first if paired with a recessive allele. BB, Rr  Recessive traits are written as ______ Lower case letters, always written second with the dominant allele. tt