Ch 11 Genetics

Essential Vocab True Breeding Traits Hybrids P F 1 F 2

Genes Alleles Genotype Phenotype Dominant Recessive Homozygous Heterozygous

Gregor Mendel’s Contribution “Father of Genetics” Worked with pea plants because they are small, easy to grow, and produced large quantities of offspring. 7 characteristics are observable on pea plants Traits-characteristics like color, height, etc.

What did Mendel do? He fertilized the plants (P1) to observe what traits were present in the offspring (F1) And….F2

Self Fertilization Pea plants self fertilize Cross Fertilization Two different pea plants fertilized Fertilization

Mendelian Inheritance Individual’s characteristics are determined by factors that are passed from one parental generation to the next.

Dominant- masks What are the dominant phenotypes? Recessive- is masked What are the recessive phenotypes?

Annotate and Predict F 1

Mendelian Inheritance and Making Predicting Allele: A form of a gene. Humans have 2 for each trait. S=Normal Skin (dominant) s=Albanism (recessive) The combination of them determines what trait we will have. Genotype  Phenotype

Recall: Dominant An organism with at least 1 dominant allele will exhibit the dominant trait. Shown by CAPITAL LETTERS (S) SS and Ss will have normal skin.

Recall: Recessive In order for a recessive trait to be expressed, two copies of that allele must be present. Shown by lower case letters (s) ss will have albanism

What does it mean? Heterozygous or Homozygous (Word dissection) Heterozygous Ss Homozygous SS and ss SS homozygous dominant ss homozygous recessive

Heterozygous or Homozygous Genotypes

Example: skin disorders…

Albanism or Normal Skin? S=normal skin s=albanism Predicting expected genotypes and phenotypes

What are the genotypes? What are the corresponding phenotypes?

What if you wanted to make a prediction for 20 offspring?