1. Introduction to Genetics
Important words to know

2. Genetics Study of heredity
Studies the way in which genetic/hereditary information is passed on from parents to offspring

3. Fertilization During sexual reproduction, when a sperm and egg meet
Produces a new cell, with some DNA from the mom and some from the dad

4. Gametes
Sex cells
Sperm
Egg

5. True-breeding Means self-pollinate
Ex: some plants have “male” and “female” sex organs, so can produce offspring identical to themselves
Ex: pea plant, apricot, avocado, grapes

6. Trait A specific characteristic Varies from one individual to another
Ex: eye color, human height, seed color, plant height

7. Chromosomes
Contain hereditary information (DNA)

8. Gene Specific unit of hereditary material located on a chromosomes
Genes code for specific traits

9. Alleles Different forms of a gene
Ex: The gene controlling hair color exists as an allele for blond hair or an allele for brown hair.
Ex: in plants, the gene controlling height either exists as an allele for tallness or an allele for shortness.

10. Principle of Dominance
Some alleles are dominant and some alleles are recessive.

11. Dominant vs. Recessive Alleles
Dominant Alleles
Recessive Alleles
An organism with a dominant allele for trait will always exhibit that trait.
Dominant expressed by capital letter
An organism with a recessive allele for a trait will show that trait if the dominant allele is not present.
Recessive expressed by lower case letter
In pea plants, the alleles for height is either T or t. Which is the recessive allele?
If we were looking at human eye color, pick a letter to represent eye color. Now show the difference between brown (dominant) and blue (recessive) alleles?

12. Hybrid Offspring from parents with different traits
Ex: yellow corn and white corn offspring with both colors
Offspring has the DNA from both parents