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Published byRalph Wilfrid Cannon Modified over 9 years ago
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Inquiry 11/19 and 11/20 Please put your test corrections and test in the inbox (even if you didn’t finish) No warm-up! Flip to section 3 of your lab book
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Learning Targets I can correctly write the genotype and phenotype of an organism. I can analyze and explain the results of dominant and recessive yeast traits.
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Class Genetics Study (Leave room for a 4-5 sentence yeast lab conclusion) Record your results as we go through the trials: Taster or non-taster Roller or non-roller Attached earlobes or free-hanging Hitchhiker's thumb or not L over R or R over L Mid-digital hair or none Right or left Freckles or none
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Class Genetics Study Record Class Data Taster or non-taster Roller or non-roller Attached earlobes or free-hanging Hitchhiker's thumb or not L over R or R over L Mid-digital hair or none Right or left Freckles or none
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Class Genetics Study 1. Which traits that we studied are dominant?
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Intro. to Genetics How do the genes you inherit make you “you”?
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History of Genetics Gregor Mendel 1822-1884 “Father of genetics” Austrian monk who studied inheritance of physical traits in pea plants
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Pea plants reproduce sexually- with male and female gametes Gametes = sperm (pollen) and eggs Peas can self-pollinate and be true- breeding True-breeding: short plants breed short plants and tall plants breed tall plants. Mendel’s Pea Plant Study
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Mendel studied these traits
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Mendel’s Crosses Mendel bred plants with different traits and studied the offspring. original parents are the P generation. offspring are the F1 (daughter/son) generation
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Mendel’s Findings When crossing parent plants (P) with different traits, all F1 plants looked the same! When crossing F1 plants, three out of four offspring looked like the parents!
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2 of Mendel’s Laws Law of Inheritance Traits are controlled by pairs of genes- with one gene coming from each parent These genes are called alleles Law of Dominance some alleles are dominant and other are recessive. Dominant – physically expressed Recessive – present but not expressed
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Key Terms Gene Sections of DNA within chromosomes Are the units of heredity Allele Alternative genes for trait Example: Height (Tall or Short); Eyes (Brown or Blue); Cheeks (Dimple or No Dimple); Hair Line (Peak or Straight)
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Dominant vs. Recessive Each gene has two possible alleles Dominant- always expressed Recessive- always hidden by a dominant allele. Example: Dimpled chin (cleft chin) is dominant D= dimpled d= non-dimpled Your two copies can be DD, Dd, or dd
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Dominant vs. Recessive Genotype= the alleles that you have for a trait Phenotype= the physical expression of those alleles A person with a dimpled chin can have the genotype DD or Dd A person with a non-dimpled chin can only have the genotype dd
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More Definitions Homozygous= two of same allele (DD or dd) Heterozygous= two different alleles (Dd- also called hybrid)
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Back to Class Genetics Answer the rest of the questions from the worksheet IN YOUR LAB BOOK.
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Yeast Lab 1.Briefly record under your prediction grid why you chose each color for each “baby”
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Yeast Lab Results/Conclusion Record the color of each offspring in each box. Conclusion Claim- which color is dominant? Evidence- how do you know? Reasoning- why does being dominant or recessive result in that color pattern?
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Punnett Squares Knowing genotypes of parents, we can predict the probability of offspring having dominant/recessive traits RR RRR rRr Results: Genotypes: 50% RR; 50% Rr Phenotypes: 100% round Ex: Peas Round seeds = R Wrinkled seeds = r
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Simple Punnett Self Test In the Griffin Family, round heads are dominant to football shaped heads. Cross a parent who is homozygous dominant with one who is heterozygous. Show the genotypic and phenotypic ratios.
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Mendel’s Laws Law of Segregation During gamete formation two chromosomes separate Each gamete contains one allele for each trait Law of Independent Assortment Traits are inherited independently of each other
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