Post on 18-Jan-2016
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
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.
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-tasterRoller or non-rollerAttached earlobes or free-hangingHitchhiker's thumb or notL over R or R over LMid-digital hair or noneRight or leftFreckles or none
Class Genetics StudyRecord Class Data
Taster or non-tasterRoller or non-rollerAttached earlobes or free-hangingHitchhiker's thumb or notL over R or R over LMid-digital hair or noneRight or leftFreckles or none
Class Genetics Study
1. Which traits that we studied are dominant?
Intro. to Genetics
How do the genes you
inherit make you “you”?
History of Genetics
Gregor Mendel 1822-1884 “Father of genetics” Austrian monk who studied inheritance
of physical traits in pea plants
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
Mendel’s Pea Plant Study
Mendel studied these traits
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
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!
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
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)
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 canbe DD, Dd, or dd
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
More Definitions
Homozygous= two of same allele (DD or dd)
Heterozygous= two different alleles(Dd- also called hybrid)
Back to Class Genetics
Answer the rest of the questions from the worksheet IN YOUR LAB BOOK.
Yeast Lab
1. Briefly record under your prediction grid why you chose each color for each “baby”
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?
Punnett Squares Knowing genotypes of parents, we can
predict the probability of offspring having dominant/recessive traits
R R
R RR RR
r Rr Rr
Results:
Genotypes:
50% RR; 50% Rr
Phenotypes:
100% round
Ex: Peas
Round seeds = R
Wrinkled seeds = r
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.
Mendel’s Laws Law of Segregation
During gamete formation two chromosomes separate
Each gamete contains oneallele for each trait
Law of Independent Assortment Traits are inherited independently of
each other