Genetics Notes Genetics - the study of how traits are inherited.

Heredity - the passing of traits from parent to offspring. These traits are controlled by genes.

What are genes?????

Genes - segments of DNA and found on chromosomes. Genes control specific traits.

Gregor Mendel

The father of genetics Studied science and math, but eventually became a monk.

He was in charge of the gardens at the monastery.

He began experimenting with pea plants.

Dominant - the form of a trait that appears to dominate or hide another form of the same trait. Recessive - the form of a trait that appears to disappear behind the dominant form of that trait.

Behind the scenes, the genes control the flower color. The genes come in pairs (because chromosomes come in pairs). One from Mom and one from Dad.

Alleles - Different forms a gene may take (for example: pink allele, white allele). Dominant and recessive alleles are represented by letters. A capital letter stands for a dominant allele and a small letter stands for a recessive allele. Always use the letter for the dominant allele.

A tool that shows how a parent's genes can combine. It is used to predict the characteristics of the offspring.

1. Which color is dominant? Recessive?

2. What letter would you pick to represent an allele for pod color? 3. How would you write letter for the dominant pod color allele?

4. How would you write the letter for the recessive pod color allele?

5. What two alleles could a yellow pea pod have? ______

6. What two of alleles could a green pea pod have? ______& ______

7. Complete the Punnett square.

8. A smooth pea is dominant over a wrinkled pea. What type of pea would have the following:

Ss - SS -

ss -

8. Create a Punnett Square for Ss x Ss. Genotype - the genetic make-up of a particular trait. Example: PP, Pp, pp

Phenotype - the physical trait of a gene. Example: pink flower, white flower

Homozygous - when the two alleles of a gene are exactly the same. Example: PP, pp. Also called purebred.

Heterozygous - when the two alleles of a gene are different. Example: Pp. Also called hybrid.