Have a seat. I will be putting you into groups when the bell rings. 

Objective I can identify how inherited traits are similar for parents and their offspring.

Genetics and Inherited Traits

What is Genetics? Genetics is the scientific study of heredity Heredity is the passing of traits from parents to their offspring

What is a Trait? A trait is a specific characteristic that varies from one individual to another. Examples: Brown hair, blue eyes, tall, curly hair

Who are you? This question can be answered many ways… Personality traits Kindness Vegetarian Athlete Love music These are traits you can control Emphasize genetic effects (blood type) versus environmental effects (eating etc.) . Nature versus nurture idea.

Who are you? This question can be answered many ways… Physical Traits Height Eye color Hair color and texture Foot size Bone strength These are traits you can’t control Kobe Bryant and Shaquille O’Neal

What determines your physical traits? GENES Genes are molecules in every cell that act like recipes. They tell your cells how to behave by coding for proteins. Genes determine how we look, move and grow. You get your genes from your parents. Genes are not gifts, they enable you to “be.” Every living thing has genes: from bacteria to plants to humans.

A bundle of DNA containing many genes Chromosome: Chromosome A bundle of DNA containing many genes

Different versions of the same gene B b Alleles: Different versions of the same gene

A cassette is a large bundle of tape containing many tracks. It is like a… chromosome Tape: it is used to record information it is like… One song or track on the tape is like a… gene DNA B b Different versions of the same song are like… alleles

The physical appearance of an organism Phenotype: The physical appearance of an organism Red flowers Brown eyes White flowers Blue eyes

The types of genes an organism has. Genotype: The types of genes an organism has. B b B b Genotype: BB Genotype: Bb Genotype: bb

Dominant allele: The stronger allele. B b The stronger allele. It is always shown when it is present… … it cannot be hidden by another allele.

Recessive allele: The weaker allele. b The weaker allele. It can be masked (hidden) by another allele… … it is only shown when two copies are present.

Genotype vs Phenotype Genotype Phenotype The genetic makeup Symbolized with letters BB, bb, or Bb Phenotype Physical appearance of the organism Expression of the trait Short, tall, yellow, smooth, etc. We use two letters to represent the genotype A capital letter represents the dominant allele A lowercase letter represents the recessive allele

If an individual has two of the same alleles the individual is… If an individual has two different alleles the individual is… …homozygous …heterozygous b B B b The prefix homo- means… ‘same’ The prefix hetero- means… ‘different’

Early Genetics The study of genetics began with observations made by Gregor Mendel. After noticing that the flowers on his pea plants were either violet or white, Mendel began to study the segregation of heritable traits. Between 1856 and 1863 he cultivated and tested at least 28,000 pea plants.

Some traits observed by Mendel Cotyledon: the first leaves to appear from a germinating seed.

Punnett Squares The Punnett square is the standard way of working out what the possible offspring of two parents will be.

How to set up a Punnett Square Begin by constructing a grid of two perpendicular lines.

Put the genotype of one parent across the top B B b Put the genotype of one parent across the top and the other along the left side. Notice only one letter goes above each box. It does not matter which parent’s genotype goes on either side.

The letters from the top get moved down the columns. B B The letters from the top get moved down the columns. b Usually write the capital letter first B B The letters on the left side move across the rows. Bb Bb b Bb Bb

Using a Punnett Square In rabbits, black fur color is dominant to white. What is the probability of producing a white rabbit if two heterozygous rabbits mate?

Using a Punnett Square Step 1: figure out the genotype of the parents. Black is dominant to white. B - black b - white Parents are heterozygous. Bb - dad Bb - mom

Using a Punnett Square Bb Bb Step 2: set up a Punnett Square. B b B b

Using a Punnett Square Step 3: Fill in the Punnett Square. B b B b

Using a Punnett Square Step 3: Fill in the Punnett Square. B b BB B b

B b B b Using a Punnett Square BB Bb Step 3: Fill in the Punnett Square. B b BB Bb B b

B b B b Using a Punnett Square BB Bb Bb Step 3: Fill in the Punnett Square. B b BB Bb B Bb b

B b B b Using a Punnett Square BB Bb bb Bb Step 3: Fill in the Punnett Square. B b BB Bb B bb Bb b

B b B b Using a Punnett Square BB Bb bb Bb Step 4: Count the results. Genotypes 1 homozygous dominant B b BB Bb B bb Bb b

B b B b Using a Punnett Square BB Bb bb Bb Step 4: Count the results. Genotypes 1 homozygous dominant 2 heterozygous B b BB Bb B bb Bb b

B b B b Using Punnett Square BB Bb bb Bb Step 4: Count the results. Genotypes 1 homozygous dominant 2 heterozygotes 1 homozygous recessive B b BB Bb B bb Bb b

B b B b Using a Punnett Square BB Bb bb Bb Step 4: Count the results. Genotypes 1 homozygous dominant 2 heterozygotes 1 homozygous recessive Phenotypes B b BB Bb B bb Bb b

B b B b Using a Punnett Square BB Bb bb Bb Step 4: Count the results. Genotypes 1 homozygous dominant 2 heterozygotes 1 homozygous recessive Phenotypes 3 black fur B b BB Bb B bb Bb b

B b B b Using a Punnett Square BB Bb bb Bb Step 4: Count the results. Genotypes 1 homozygous dominant 2 heterozygotes 1 homozygous recessive Phenotypes 3 black fur 1 white fur B b BB Bb B bb Bb b

Probability and Punnett Squares In rabbits, black fur color is dominant to white. What is the probability of producing a white rabbit if two heterozygous rabbits mate? 1 in 4 or 25%

Punnett Squares Now that we have learned the basics of genetics lets walk through some examples using Punnett Squares.

Red hair (R) is dominant over blond hair (r) Red hair (R) is dominant over blond hair (r). Make a cross between a heterozygous red head and a blond. R r r Rr rr Rr rr What percentage of the offspring will have red hair? 50%

T t t Tt tt Tt tt What are the percentage of phenotypes? 50% tall Let’s try some more… In pea plants, tall pea plants (T) are dominant over short pea plants (t). Construct a Punnett Square for a heterozygous tall pea plant and a short pea plant. T t What are the percentage of phenotypes? t Tt tt 50% tall 50% short Tt tt

Black eyes (R) are dominant over red eyes (r) in rats Black eyes (R) are dominant over red eyes (r) in rats. Make a cross between a homozygous rat with black eyes and a rat with red eyes. R R What is the possibility of a red eye off springs? r Rr Rr Rr Rr 0%  Discuss with students other possible answers

Easter Egg Genetics Lab

Easter Egg Genetics Lab 1. Choose one egg, but do not open it yet. 2. Record the Phenotypes and Genotypes of your egg. 3. Place the genotypes of your egg into the Punnett Square. 4. Complete the Punnett square. 5. Determine your results including the genotypes and phenotypes of the offspring. 6. Open your egg – do your results match the results inside the egg? a. If yes, then place the egg back together and pick another egg! b. If no, check your work and make corrections. 7. Continue until you have completed 6 eggs.

Easter Egg Genetics Lab 1. Choose one egg, but do not open it yet. 2. Record the Phenotypes and Genotypes of your egg. 3. Place the genotypes of your egg into the Punnett Square. 4. Complete the Punnett square. 5. Determine your results including the genotypes and phenotypes of the offspring. 6. Open your egg – do your results match the results inside the egg? a. If yes, then place the egg back together and pick another egg! b. If no, check your work and make corrections. 7. Continue until you have completed 6 eggs.

Easter Egg Genetics Lab 1. Choose one egg, but do not open it yet. 2. Record the Phenotypes and Genotypes of your egg. 3. Place the genotypes of your egg into the Punnett Square. 4. Complete the Punnett square. 5. Determine your results including the genotypes and phenotypes of the offspring. 6. Open your egg – do your results match the results inside the egg? a. If yes, then place the egg back together and pick another egg! b. If no, check your work and make corrections. 7. Continue until you have completed 6 eggs.

Easter Egg Genetics Lab 1. Choose one egg, but do not open it yet. 2. Record the Phenotypes and Genotypes of your egg. 3. Place the genotypes of your egg into the Punnett Square. 4. Complete the Punnett square. 5. Determine your results including the genotypes and phenotypes of the offspring. 6. Open your egg – do your results match the results inside the egg? a. If yes, then place the egg back together and pick another egg! b. If no, check your work and make corrections. 7. Continue until you have completed 6 eggs.

Easter Egg Genetics Lab 1. Choose one egg, but do not open it yet. 2. Record the Phenotypes and Genotypes of your egg. 3. Place the genotypes of your egg into the Punnett Square. 4. Complete the Punnett square. 5. Determine your results including the genotypes and phenotypes of the offspring. 6. Open your egg – do your results match the results inside the egg? a. If yes, then place the egg back together and pick another egg! b. If no, check your work and make corrections. 7. Continue until you have completed 6 eggs. 2 (BB) Blue and 2 (Bb) Green

Easter Egg Genetics Lab 1. Choose one egg, but do not open it yet. 2. Record the Phenotypes and Genotypes of your egg. 3. Place the genotypes of your egg into the Punnett Square. 4. Complete the Punnett square. 5. Determine your results including the genotypes and phenotypes of the offspring. 6. Open your egg – do your results match the results inside the egg? a. If yes, then place the egg back together and pick another egg! b. If no, check your work and make corrections. 7. Continue until you have completed 6 eggs. 2 Blue Pieces and 2 Green Pieces

Easter Egg Genetics Lab 1. Choose one egg, but do not open it yet. 2. Record the Phenotypes and Genotypes of your egg. 3. Place the genotypes of your egg into the Punnett Square. 4. Complete the Punnett square. 5. Determine your results including the genotypes and phenotypes of the offspring. 6. Open your egg – do your results match the results inside the egg? a. If yes, then place the egg back together and pick another egg! b. If no, check your work and make corrections. 7. Continue until you have completed 6 eggs. 2 Blue Pieces and 2 Green Pieces

Easter Egg Genetics Lab 8. When finished, fill in the results chart and answer the discussion questions.