Inheritance NotesPage 27

FYI

• Practice summarizing! Do not copy word-for-word.

• If you run out of space, do NOT go to the next page. Attach a piece of paper to page 27.

Gregor Mendel

• Called the “Father of Genetics”

• Studied many different characteristics of pea plants

• Examples: flower color and plant height

• His experiments with pea plants helped us understand how traits are inherited

• He thought there was “something” in each plant that controlled its traits

• That “something” is known today as genes

Genes

• Every characteristic is controlled by 2 genes• 1 gene is from the mother

• 1 gene is from the father

Allele

• An allele is a form of a gene• There are 2 possible forms

• dominant or recessive

• Capital letters represent dominant alleles (P, G, T)

• Lowercase letters represent recessive alleles (p, g, t)

Dominant vs. Recessive Genes

• Dominant• An offspring that

inherits one or more dominant genes will show the dominant trait.

• Dominant genes will mask (cover up) a recessive gene.

• Recessive• An offspring that

inherits 1 recessive gene from 1 parent and 1 recessive gene from the other parent will have 2 recessive genes. This means that there is no dominant gene to mask the recessive trait in the offspring.

Phenotype

• Describes an organism’s physical appearance (what the trait looks like)• Example: blue eyes, purple flower, etc.

Genotype

• Two letters representing a gene pair• Examples: RR, Rr, or rr

Homozygous Genotype

• The prefix ‘homo’ means ‘same’

• Both alleles in a genotype are the same• Both are dominant OR both are recessive

• Mendel’s parent generation plants were homozygous• GG = green peas

• gg = yellow peas

Homozygous Genotype Continued

•Homozygous dominant• Both alleles are dominant

• Example: GG

•Homozygous recessive• Both alleles are recessive

• Example: gg

Heterozygous Genotype

• The prefix ‘hetero’ means ‘different’

• The alleles in a genotype are different• One is dominant and one is recessive

• Mendel’s F1 generation plants were heterozygous• Gg = green peas

Ticket Out the Door

• Now that you’re done with your notes, complete the Inheritance Notes Ticket Out the Door.• You may look back at any of these slides and/or your

notes on page 27 to complete this assignment.

• When you’re done, put it in the center of your table.