🧬 Genetics — Advanced#

Scope — Population and quantitative genetics, epigenetics, genome editing concepts, and modern genomic analysis methods.

Key concepts#

• Population genetics — allele frequency dynamics, selection coefficients, drift, migration, and mutation.
• Epigenetics — heritable changes in gene expression not caused by DNA sequence changes (e.g., DNA methylation, histone modification).
• Genome technologies — CRISPR/Cas systems, high‑throughput sequencing, GWAS, and comparative genomics.

Seed Q&A triads#

• Q: What does a genome‑wide association study (GWAS) identify?
  A: Statistical associations between genetic variants (usually SNPs) and traits across populations, highlighting loci that contribute to phenotypic variation.

• Q: How does CRISPR/Cas9 achieve targeted genome edits?
  A: A guide RNA directs Cas9 to a complementary DNA sequence where Cas9 creates a double‑strand break; repair pathways (NHEJ or HDR) then introduce edits.

• Q: What is the difference between hard and soft selective sweeps?
  A: A hard sweep arises from a single new beneficial mutation rapidly fixing; a soft sweep involves multiple beneficial alleles or standing variation contributing to adaptation.

Contributor prompts and extensions#

• Add a worked example estimating selection coefficient from allele frequency change over generations.
• Include a brief primer on interpreting GWAS Manhattan plots and common pitfalls (population stratification, multiple testing).
• Provide a short note on ethical considerations for genome editing and data sharing.