1. How are traits passed from one generation to the next?

5. Big Idea Genes  RNA  Protein  Traits
The inheritance of each trait is determined by genes that are passed on to descendants unchanged.
An individual inherits genes from each parent for each trait.
A trait may not show up in an individual, but can still be passed on to the next generation.

6. Genetic Vocabulary
Character = something that can be inherited by the next generation, such as flower color or blood type
Trait = a variant of a character, such as purple or white flowers, or Type A or B blood
Alleles = Alternative forms of a gene – there are 3 versions of blood type gene = A, B, and O

7. Humans have two copies of EVERY gene, one inherited from the mother and the other from the fatherB AB

8. Heterozygous = alleles inherited from mom and dad were different Homozygous = alleles inherited from mom and dad were the same

9. Phenotype  expression of genes, what you look like.
What it looks like
(Traits that SHOW)
Phenotype  expression of genes, what you look like.

10. Genotype  the genes that control characteristics
What Genes it has
(May or may not show)

11. Dominant – always shows if the individual has this allele (Capital Letter) Recessive- will only show if the individual has two copies of this allele. Trait hides behind the dominant allele (Lower case letter)

13. Incomplete Dominance
One allele is not completely dominant over another allele.

14. Codominance
Both alleles contribute to the phenotype
Heterozygous

15. How to Predict if offspring will inherit and express a trait:
Parents must possess the genes for the kids to get them.
Genes are independently sorted during gamete formation. XY

17. Punnett Squares are a tool for predicting the genotype of the offspring!
Aa & Aa

18. Ratios and %’s
XX and XY

19. Blood Types

20. Codominance in humans
Protein that controls cholesterol levels in the blood.
Heterozygous form of the gene produce two different forms of the protein, each with a different effect on cholesterol levels.

21. Polygenic Traits Traits controlled by two or more genes.
Having many genes
There are at least three genes involved in making the reddish-brown pigment in the eyes of fruit flies.

22. Polygenic Traits Skin color in humans
Often shows a wide range of phenotype
Skin color in humans
More than 4 genes that control this trait.

23. Sex Linked Genes
Inheritance of genes located on the X and Y chromosomes
More than 100 sex linked genetic disorders mapped on the X chromosome.
Y chromosome only contains a few genetic disorders.

24. Colorblindness
Most common form of colorblindness; red-green males
Male have just 1 X chromosome. Thus, all X-linked alleles are expressed in male, even recessive.
1-100 females has colorblindness

25. Hemophilia
Protein for normal blood clotting is absent.
1-10,000 males

26. Duchenne Muscular Dystrophy
Progressive weakening and loss of skeletal muscle
males