WHAT:EXTRA NOTES: WHO: WHEN: WHERE: HOW: WHY: APPLY PART 1: APPLY PART 2: (SKIP SPACE BETWEEN EACH POINT) TOPIC: Genetics & Heredity Class notes: Pwpt

What: What is heredity? Genetics-study of heredity Heredity-the passing of genetic traits from parent to offspring You “inherit” traits from your parents

Examples of Genetic Traits Some Genetic Characteristics: Eye Color Hair Color Height Body Structure Facial Features Skin Color What genetic traits did you inherit from your parents? Name two genetic traits- “Nature vs. Nurture” is debated about some characteristics.

Who/When/Where Gregor Mendel-an Austrian monk; in the mid 1800s studied the genetics of pea plants. -“The Father of Genetics” *Watch Mendel Video to answer the who/when/where. eo.php?video_id=886

How are traits passed? Traits are determined by one’s genes. Genes (DNA) from both parents are given to their offspring during reproduction. DNA is the genetic material found in a cell’s nucleus. DNA acts like a set of instructions for the cell.

Dominant and Recessive Each parent has two or more forms of a gene (or letters) for a certain trait. These letters are called alleles. An allele is one of two or more forms of a gene. *Capital letters represent dominant alleles. When these alleles are present, they mask the recessive trait. They are the “stronger” alleles. *Lower case letters represent recessive alleles and are the “weaker” of the alleles. They are hidden when in the presence of a dominant allele.

Homozygous & Heterozygous If the alleles are the same, the genotype (genetic makeup) is called “homozygous”; also called “pure” Ex: HH-homozygous dominant hh-homozygous recessive If the alleles are different, the genotype is called “heterozygous”; also called “hybrid” Ex: Hh-heterozygous There are 3 possible genotypes and 2 possible phenotypes in situations exhibiting complete dominance.

Genotype vs. Phenotype Genotype=genetic makeup; what genes it has (EX: QQ, Qq, qq) Phenotype=physical characteristics; what it looks like (Ex: has dimples; lacks a widow’s peak, etc…)

Let’s Apply (Part 1) the Terms 1.What do you call the genotype… HH? 2. Hh? 3. hh?

Let’s Apply the Terms:ANSWERS HH-homozygous dominant or pure-dominant Hh-heterozygous or hybrid hh-homozygous recessive or pure-recessive

Punnett Squares Reginald Punnett ( ) Using Punnett Squares allows us to use probability to predict the genotypes and phenotypes of future offspring, if we know the genotypes of the parents. Monohybrid Punnett Square Why

Let’s Practice a Punnett Square! Watch video Practice Punnett square problems on next slide

Apply (Part 2) Practice Problem #1 A)An individual heterozygous for flower color is crossed with an individual that is homozygous dominant. (Purple is dominant to white in flower color.) Write the genotypes crossed. ____________x____________ B)Draw the Punnett square for this cross. Use the letters H and h to represent the alleles. C) What percent of the offspring will be homozygous dominant? D) What proportion of the offspring flowers will have white petals?

Practice Problem #1 Answer A)(Hh x HH) B) H h H C) What percent of the offspring will be homozygous dominant? (HH) 2/4=50% D) What proportion of the offspring flowers will have white petals? 0/4 HHHh HH

Practice Problem #2 A)A hybrid pea plant is crossed with a pure yellow pea plant. (Green is dominant to yellow in pod color.) What color is the hybrid plant? B) Write the genotypes crossed. ____________x____________ C) Draw the Punnett square for this cross. Use the letters Q and q to represent the alleles. D) What percent of the offspring will have the hybrid genotype? E) What proportion of the offspring flowers will be yellow?

Practice Problem #2 Answer A) green B) (Qq x qq) C) Q q q D) What percent of the offspring will have the hybrid genotype? 50% E) What proportion of the offspring pods will be yellow? 50% Qqqq Qq