Genetics Fundamentals and Inheritance

📋 Course Outline

1. Alleles and inheritance terms
2. Single-factor crosses
3. Genotype notation and gene loci
4. Punnett squares and offspring ratios
5. Chance, probability, and large numbers
6. Mendel’s law of segregation
7. Predicting genotypes from crosses
8. Test crosses
9. Single-gene traits in animals

📖 1. Alleles and inheritance terms

🔑 Key Concepts & Definitions

• Alleles : Alleles are alternative forms of a gene that an individual may carry.
• Dominant and recessive : Dominant and recessive describe trait forms that differ in whether they show up in the heterozygous condition.
• Homozygous and heterozygous : Homozygous means two identical alleles for a gene, while heterozygous means two different alleles for that gene.
• Recessive trait : A recessive trait is observed only when the individual is homozygous for the recessive allele.
• Dominant trait : A dominant trait is observed in both heterozygous and homozygous genotypes.

📝 Essential Points

• An individual has two copies of every gene, one from egg and one from sperm.
• A homozygous individual has two of the same allele for a particular gene.
• A heterozygous individual has two different alleles for the same gene.
• The recessive phenotype corresponds to being homozygous recessive.
• The dominant phenotype appears in both Tt and TT genotypes in the tall example.

💡 Memory Hook