Gregor Mendel and the Foundations of Genetics

Introduction to Gregor Mendel

• Austrian monk known as the "father of genetics"
• Conducted experiments in a monastery garden with pea plants
• Aim: To understand life and heredity through plant characteristics

Mendel's Experiments with Pea Plants

• Focused on variations in plant characteristics: height, seed shape, seed color, flower color
• Cross-pollination experiments:
  • Crossed tall plants with short plants
  • Crossed plants with yellow peas with green peas
• Observed offspring (F1 generation): noticed disappearance of certain traits

Key Observations

• In the F1 generation, traits like short and green disappeared
• In the F2 generation, hidden traits reappeared:
  • Ratio approximately 3:1 (dominant:recessive)

Mendel's Laws of Heredity

1. Law of Segregation

• Genes exist in multiple forms called alleles
• Example: Seed color gene with alleles for yellow (Y) and green (y)
• During gamete formation, alleles segregate so each gamete has one allele
• Fertilization results in offspring with two alleles per gene (one from each parent)

2. Law of Dominance

• Alleles can be dominant or recessive
• Dominant alleles mask the expression of recessive alleles
• Example: Purple flower allele (dominant) masks white flower allele (recessive)

3. Law of Independent Assortment

• Traits are passed independently of each other
• Alleles for different genes are inherited independently
• Example: A plant's height does not affect seed color

Significance of Mendel's Work

• Mendel's findings form the foundation of heredity and genetics
• Though genetics has advanced, these laws remain fundamental
• Understanding applies to humans, genetic disorders, and exceptions

Conclusion

• Genetics is more complex than initially understood by Mendel
• Continues to be a fascinating field of study
• Leslie Samuel encourages continued exploration of genetics with Interactive Biology

Further Exploration

• Application of Mendel's laws to humans
• Genetic disorders and exceptions to Mendel's laws

Presenter: Leslie Samuel from Interactive Biology

• Aim: Making biology engaging and fun