Essential Question: How is the combination of genes important in determining the inheritance of biological traits? Standards: S7L3a. Explain the role of genes and chromosomes in the process of inheriting a specific trait. S7L3c. Recognize the selective breeding can produce plants and animals with desired traits. Instructional Approach(s): The teacher should review the essential question and the standards that align to the essential question

Let’s Review… Cell/Nucleus Chromosome DNA Gene Instructional Approach(s): Review with students the information on the slide. Cell/Nucleus Chromosome DNA Gene

Sexual Reproduction and Heredity Instructional Approach(s): Present information in the slide. Remind student that each reproductive cell may contain different traits to pass along to the offspring.

Sexual Reproduction and Heredity Instructional Approach(s): Present information in the slide. Humans have 46 total chromosomes in 23 pairs. One chromosome of each pair comes from each parent.

Each set of Genes codes for a different trait Chromosomes Each set of Genes codes for a different trait Instructional Approach(s): Review the information in the slide.

Review of Concepts http://learn.genetics.utah.edu/content/inheritance/intro/ Instructional Approach(s): Show video clip.

The various forms of the same gene are called Alleles. Chromosome Pair From Mom From Dad While both chromosomes have the same genes, they can have different forms of these genes. Gene for making Earwax Gene for Eye Color For example, in the chromosome to the left one form of the gene for eye color will give you blue eyes and the other form will give you brown eyes. Instructional Approach(s): Present information in slide. Have student fill in vocabulary on notes sheet. The various forms of the same gene are called Alleles.

Alleles are usually represented by letters. Instructional Approach(s): Present information in the slide.

Phenotype An organism’s phenotype describes the physical characteristics that can be observed. Instructional Approach(s): Present information in the slide. Students will fill in vocabulary. View video clip. https://www.23andme.com/gen101/phenotype/

Genotype An organism’s genotype describes the actual genes an organism has. Your genotype is not always obvious from your phenotype. Instructional Approach(s): Present information in the slide. Students will fill in vocabulary.

Phenotype and Genotype Instructional Approach(s): Present information in slide, emphasizing differences.

Alleles, Phenotype and Genotype Instructional Approach(s): See resources for a possible demonstration to do prior to introducing Dominant and Recessive

Sometimes your genes contain information that is not expressed in your phenotype. Instructional Approach(s): Present information in the slide. Emphasize the allele not expressed in the phenotype

[represented by a Capital Letter] A Dominant allele is one that is expressed in the phenotype even if only one copy is present in the genotype [represented by a Capital Letter] Instructional Approach(s): Present information in the slide. Students will fill in vocabulary.

A Recessive allele is one that is expressed in the phenotype only when two copies of it are present [represented by a lower case Letter] Instructional Approach(s): Present information in the slide. Students will fill in vocabulary.

If one chromosome in the pair contains a dominant allele and the other contains a recessive allele, the dominant allele will be expressed in your phenotype. Instructional Approach(s): Present information in the slide.

Alleles that have the same form of the same gene [two capital or two lower case letters] are called Homozygous or Pruebred Instructional Approach(s): Present information in the slide. Students will fill in vocabulary.

Alleles that have two different forms of the same gene [a capital and a lower case letter] are called Heterozygous or Hybrid Instructional Approach(s): Present information in the slide. Students will fill in vocabulary.

Instructional Approach(s): Present information in the slide.

Incomplete dominance When both alleles are present and are both expressed in the phenotype. The hybrid is a blend of both alleles. Example: A white flower and a red flower making a pink flower

COdominance both alleles are equally strong and both alleles are visible in the hybrid genotype. Example: A black cow and a white cow create a black and white cow.

Genotype, Phenotype, Homozygous and Heterozygous Practice handouts Genetic With a Smile Instructional Approach(s): Activities for applying the combination of genes [it is not intended for all of the activities to be completed. Select one or two to use initially and another might be used for reinforcement during differentiation]:

How does the combination of parent alleles affect offspring? Instructional Approach(s): Present information in slide. Student will fill in notes sheet. A Punnett Square is used to show the possible combination of genes.

A Punnett Square is used to illustrate how a parent’s alleles might combine in offspring. Instructional Approach(s):Present information in slide.

Punnett Square https://www.youtube.com/watch?v=V_pl5lcSUFg Parent Alleles Offspring Instructional Approach(s): Show the video and the Punnett Square to reinforce the concepts

Let’s Look at this Example Instructional Approach(s): Present information in the slide. Go through the process of how each part of the Punnett square is derived. Dd Dd d

What percent of the offspring will have a double tail? 2 out of 4 squares have a double tail = 50% What percent of the offspring will have a normal tail? 2 out of 4 squares have a normal tail = 50% Instructional Approach(s): Present information in the slide, showing how results inside the square obtained. Demonstrate calculation of probabilities. Dd Dd d

Bb and bb Rusty (bb) Bb 50% 50% With a seat partner, examine the following Punnett Square where B is dominant for brown eyes and b is recessive for blue eyes. 1. Identify the parent alleles. Bb and bb 2. Which parent’s alleles are homozygous? Rusty (bb) 3. Identify the heterozygous alleles? Bb 4. What percent of Rusty and Carrie’s offspring will have Brown eyes? Instructional Approach(s): Have students turn to a partner and discuss the questions on the slide. Partners can be determined by the students or the teacher can provide more specific directions such as turn to the person directly in front/behind you or to the right/left of you, etc. It may be necessary to have a group of three if you have an uneven number of students. Do not allow more than 2-3 minutes of discussion time. The teacher should be walking around listening and redirecting discussions as needed. When ready, the teacher can ask groups or the class each question and click the mouse to reveal the answer. 50% 5. What percent of Rusty and Carrie’s offspring will have Blue eyes? 50%

Incomplete dominance : Homozygous R R W R W R W W R W R W Homozygous

Codominance : Homozygous W W B B W B W B B W B W Homozygous

Punnett Squares and Combination of Genes Activities [see resources] Instructional Approach(s): Activities for applying the combination of genes [it is not intended for all of the activities to be completed. Select one or two to use initially and another might be used for reinforcement during differentiation]:

Video Clip Reviewing Genetics Genetics Rap https://www.youtube.com/watch?v=_IOIx__UJ5g Video Clip Reviewing Genetics Instructional strategy(s): View video clips. https://www.youtube.com/watch?v=Mehz7tCxjSE

Selective Breeding is the process of selecting and breeding parent organisms to pass on particular trait to offspring. Instructional Approach(s): Have students fill in notes sheet.

Instructional Approach(s): “Common ancestor” is covered in the evolution unit. Follow the illustration to show that people sometimes select dogs to breed with each other to produce a desired offspring (as in traits judges may look for in an individual dog for a dog show)

Instructional Approach(s): Present information in the slide Instructional Approach(s): Present information in the slide. Students may use this as an example to fill in their notes sheet, or discuss other examples with an elbow partner.

Selective Breeding Activities [see resources] Instructional Approach(s): Activities for applying the combination of genes [it is not intended for all of the activities to be completed. Select one or two to use initially and another might be used for reinforcement during differentiation]:

Combination of Genes Differences or variations in DNA are what make one organism different from another Sometimes there are accidental changes in DNA. These changes can then be passed to offspring Mutations are any changes in DNA Instructional Approach(s): Prior to showing the first bullet, you may want to do the Mutation Introduction demonstration. Fill in notes sheet.

Mutation Activities [see resources] Instructional Approach(s): Activities for applying the combination of genes [it is not intended for all of the activities to be completed. Select one or two to use initially and another might be used for reinforcement during differentiation]:

Pedigree A pedigree is a tool geneticists use to trace genetic traits through a family. Parents Instructional Approach(s): Present information in the slide. Discuss the key (noting that the particular trait is not specifically identified) and trace the trait through the pedigree. Generation 1 Generation 2

Punnett Square Pedigree A Punnett Square illustrates the probability of what could happen concerning a trait when organisms sexually reproduce. A Pedigree illustrates what has happened during several generations of reproduction related to the same trait. Instructional Approach(s): Compare and contrast a Punnett Square and a Pedigree.

Pedigree Activities [see resources] Instructional Approach(s): Activities for applying the combination of genes [it is not intended for all of the activities to be completed. Select one or two to use initially and another might be used for reinforcement during differentiation]:

Combination of Genes Summarizer Instructional Approach(s): Each student should complete the summarizer. The teacher should use the summarizer to determine the level of student mastery and if differentiation is needed.