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.