1. Mendelian Genetics

2. Genetics
Genetics is the study of heredity Heredity is the passing of traits from parent to offspring Gregor Mendel is considered the Father of Modern Genetics

3. Genetics Why did Mendel use pea plants? Easy to grow
Make lots of offspring
Can manipulate pollination

4. Genetics Peas can self- fertilize (pollinate flowers on same plant)
Peas can cross- fertilize (pollinate flowers on a different plant)

5. Genetics
Peas have several traits with only 2 contrasting forms

6. Mendel’s 3 Step Experiment
Step 1: Produce the P (parent) generation
Parents are true-breeding plants created by self- fertilization

7. Mendel’s 3 Step Experiment
Step 2: Produce the F1 generation
Cross 2 different parent plants together
All F1 offspring looked alike

8. Mendel’s 3 Step Experiment
Step 3: Produce the F2 generation
Cross any 2 F1 plants together
Offspring come out in a 3:1 ratio

9. Mendel’s Conclusions
Parents transmit information about traits to their offspring using gametes, or sex cells
Females make egg cells (ovum)
Males make sperm cells

10. Where did your genes come from?
Mendel’s Conclusions
Each individual has 2 genes for each trait
What is a gene?
segment of DNA that codes for a trait
Where did your genes come from?
your parents

11. Mendel’s Conclusions
If the 2 units you inherit are the same you are homozygous
ex. purple & purple (P generation)
If the 2 units you inherit are different you are heterozygous
ex. purple & white (F1 generation)

12. Mendel’s Conclusions
The different forms of a gene are called alleles (these are the trait choices)
An individual’s alleles (genes) are its genotype

13. Mendel’s Conclusions
The physical appearance that results from the alleles is the phenotype

14. Mendel’s Conclusions Not all alleles get expressed:
the dominant allele is ALWAYS expressed when present
 symbol is a CAPITAL letter (P)
the recessive allele is covered up in the heterozygous condition
 symbol is a lower-case letter (p)