🧬 Genetics — Intermediate#

Scope — Mendelian inheritance, linkage, basic molecular techniques, and regulatory elements affecting gene expression.

Key concepts#

• Mendelian ratios — dominant/recessive inheritance patterns and Punnett square predictions.
• Linkage and recombination — genes close on a chromosome tend to be inherited together; recombination frequency maps distance.
• Regulatory DNA — promoters, enhancers, silencers, and transcription factors control expression.

Seed Q&A triads#

• Q: How does recombination frequency relate to genetic distance?
  A: Recombination frequency approximates map distance in centimorgans; higher frequency implies greater separation on the chromosome.

• Q: What is a promoter and why is it important?
  A: A promoter is a DNA sequence where RNA polymerase and transcription factors assemble to initiate transcription; it determines when and where a gene is expressed.

• Q: How do dominant negative mutations affect phenotype?
  A: A dominant negative allele produces a product that interferes with the wild‑type protein’s function, causing a phenotype even when a normal allele is present.

Short exercises#

• Predict offspring genotypes for a dihybrid cross with independent assortment; then modify for linked genes and discuss expected ratios.