Do now question
What is genetics and why do scientists study genetics?
Intro to GeneticsMs. Bush
Genetics Unit
What are genes?
Why study genetics?
Gregor Mendel “Father of genetics”
• Born in 1822• Studied science and math
at Univ. of Vienna• Austrian Monk who
studied inheritance• Teacher and gardener• Worked with pea plants
and cross pollination
• Mendel did originally started his studies with mice not peas.
• The other monks did not approve of him breeding mice…plus they smelled bad!
Mendel and Pea Plant
“Pisum sativum”Garden pea
Mendel’s Experiments
Mendel’s Experiments
Mendel’s Laws
1. Law of Dominance – some traits are stronger than others and thus will appear more frequently in the offspring
2. Law of Segregation – alleles of same trait separate from each other during the formation of gametes (sex cells)
3. Law of Independent Assortment- genes for different traits can segregate independently during formation of gametes
Traits – Dominant and Recessive
Practice
Circle the following letters that represent dominant (stronger) traits?
T b M V c Y r w Q P L i
Circle the following letters that represent recessive (weaker) traits?
K U y E O c q A X m z R
Genotype and Phenotype
Genes are sorted in to the gametes (sex cells of an organism) and due to independent assortment, we can think of traits as sorting separate. Genotype-
Phenotype-
PracticeAssume Y means dominant yellow and y means recessive green. (Pure-breeding means YY or yy)•What is the phenotype and genotype of F1?•What is the phenotype(s) and genotype(s) of F2?
Homozygous and Heterozygous
Practice
Circle the homozygous recessive pairs:rr TT Tt Gg HH bb Nn WW yy Pp CC qq
Circle the heterozygous pairs:Oo ii LL Gg Jj DD ww VV bb zz Hh Ee SS kk
Circle the homozygous dominant pairs:Tt UU Rr Qq XX mm Dd Ff YY Oo BB Aa
Homework
Genetics Problem Set #1 due Wednesday, April 25.
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