Genetics and Inheritance Lecture

Introduction

• Focus on genetics and inheritance.
• Discusses why physical traits like eye color and shape are inherited.
• Encourages participation via Facebook and Twitter.

Resources

• Show notes, videos, and schedules available for download.
• New option to view notes on smartphones for those without a PDF viewer.

Key Concepts

Inheritance

• Inheritance refers to characteristics passed from parents to offspring.
• Inherited traits make individuals unique yet connected to family.

Genetics

• Study of how traits are passed down.
• Includes concepts of genes, alleles, chromatin, chromosomes, phenotype, and genotype.

Important Definitions

• Genetics: Study of heredity and the variation of inherited traits.
• Inheritance: Characteristics received from parents.
• Phenotype: Observable traits (e.g., eye color).
• Genotype: Genetic makeup; not visible.
• Homologous Chromosomes: Pairs of chromosomes containing the same genes.
• Genes: Units of inheritance found on chromosomes.
• Alleles: Different forms of a gene located at the same point on homologous chromosomes.

Mendel's Experiments

• Conducted by Gregor Mendel, known as the father of genetics.
• Used pea plants due to their ease of cultivation, clear traits, and ability to self- or cross-pollinate.
• Discovered that traits are inherited as discrete units.

Mendel's Laws

1. Law of Dominance: One trait can dominate or mask another in offspring.
2. Law of Segregation: Alleles segregate during gamete formation, ensuring offspring acquire one from each parent.

Crossing and Genetic Diagrams

• Monohybrid Cross: Involves one pair of contrasting traits.
• Dihybrid Cross: Involves two pairs of contrasting traits.
• Punnett Square: Tool to predict offspring genotypes from parental genotypes.

Problem Solving

1. Format for solving genetic problems:

   • Use phenotype and genotype steps.
   • Include gamete formation through meiosis, and fertilization process.
   • Calculate expected ratio of genotypes and phenotypes in offspring.

2. Example problems:

   • Homozygous vs. heterozygous crosses affect offspring ratios.
   • Dominant and recessive alleles influence observable traits.

3. Challenge questions:

   • Understanding outcomes of crosses (e.g., two heterozygous tall pea plants).
   • Explaining genetic outcomes in terms of dominance and segregation.

Conclusion

• Discussion about reliability and validity of Mendel's experiments.
• Importance of understanding genetic terminology and cross methods.
• Reinforcement of genetic concepts through problem-solving and examples.

Additional Notes

• Participate actively in lessons by asking questions.
• Continuous learning and application of concepts in genetic problems.