Genetics

Questions? If you still have questions on Punnett squares and genetics once you’ve been through the PowerPoint, watch YOUTUBE videos. Also, write down you questions for me to answer in class. Here are a couple helpful YouTube Link: https://www.youtube.com/watch?gl=US&hl=en&client=mv- google&feature=fvwrel&v=prkHKjfUmMs&rl=yes&nomobile=1 https://www.youtube.com/watch?v=i-0rSv6oxSY

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On an even page in your notebook draw the picture to the right and fill in each line with descriptions from the list below. Genotype Phenotype Trait Purebred Hybrid Homozygous Dominant Homozygous Recessive Heterozygous Allele Dominant Allele Recessive Allele Genotype Genotype Genotype Homozygous Dominant Homozygous Recessive Heterozygous Purebred Purebred Hybrid Trait Phenotype Trait Phenotype Genotype Trait Trait Allele Dominant Allele Genotype Hybrid Heterozygous

Answer the following questions beside your chart. Traits # Detached Earlobes Attached Earlobe Dimples No Dimples Freckles No Freckles Cleft Chin No cleft Brown / Black hair Blonde Hair Brown Eyes Gray / Blue Eyes Answer the following questions beside your chart. What is the difference between a dominant and recessive allele? The dominant allele is always expressed when present (HH , Hh). The recessive allele is only expressed when the dominant is absent (hh). If you were a scientist and only had a chart of a populations traits, how could you decide what traits were dominant and what were recessive? The traits that had the highest number in the population would be dominant. There are three different genotype combinations HH , Hh , hh. The dominant allele has a 2/3 chance of being expressed over a recessives 1/3 chance.

Punnett square #2 is incorrect Punnett square #2 is incorrect. The Alleles move straight down or straight across. They can not be moved diagonal into the Punnett square. The upper case A is incorrect. It should be two lower case a’s a a A a A a aa a Aa Aa a aa A a Aa Aa aa aa Aa Aa aa Aa 1 2 3

How to complete a Punnett Square – Write on blank side of half sheet Step 1 – Draw the 4 square Step 2 – Put parent allele’s on the outside of Punnett square. Trait – Eye Color Alleles - Brown Eyes and Blue Eyes E = Brown e= blue Male / Father alleles E e Female / Mom Alleles E e

EE Ee ee Ee E e Trait – Eye Color Alleles - Brown Eyes and Blue Eyes Male / Father alleles E e Step 3- Bring dad alleles down Bring mom alleles across Step 4- Determine probability/percentage of each genotype Percentage - 75% chance of brown eyes 25% chance of blue eyes Female / Mom Alleles E e EE Ee ee Ee https://www.youtube.com/watch?gl=US&hl=en&client=mv-google&feature=fvwrel&v=prkHKjfUmMs&rl=yes&nomobile=1 Trait – Eye Color Alleles - Brown Eyes and Blue Eyes E = Brown e= blue

G g g Gg gg gg is homozygous recessive and 50% Gg gg 50% T T 100% t Tt Tt Tt Tt tt is homozygous recessive and 0 %