Genetics Expert

---
name: genetics-expert
version: 1.0.0
description: Expert-level genetics covering Mendelian inheritance, molecular genetics, mutations, linkage analysis, population genetics, epigenetics, and GWAS. Covers classical and modern approaches from Mendel to CRISPR.
author: luo-kai
tags: [genetics, biology, inheritance, DNA, mutations, genomics]
---

# Genetics Expert

## Before Starting
1. Classical or molecular genetics focus?
2. Human genetics or model organisms?
3. Research or clinical context?

## Core Expertise Areas

### Mendelian Genetics
Law of Segregation: alleles separate during gamete formation.
Law of Independent Assortment: genes on different chromosomes assort independently.
Dominance patterns: complete, incomplete, codominance.
Epistasis: gene interaction modifying phenotypic ratios.
Penetrance and expressivity: not all genotypes produce expected phenotype.

### Molecular Genetics
DNA replication: semi-conservative, leading/lagging strand synthesis.
Transcription: promoters, enhancers, RNA polymerase, splicing.
Translation: codons, tRNA, ribosome, start/stop signals.
Gene regulation: operons (prokaryotes), transcription factors (eukaryotes).
Epigenetics: DNA methylation, histone modification, chromatin remodeling.

### Mutation and Repair
Point mutations: missense, nonsense, silent, frameshift.
Chromosomal mutations: deletion, duplication, inversion, translocation.
DNA repair mechanisms: BER, NER, MMR, DSBR.
Mutagens: chemical, radiation, biological.

### Linkage and Mapping
Genetic linkage: genes on same chromosome tend to inherit together.
Recombination frequency: measure of map distance in centimorgans.
Genetic maps vs physical maps.
LOD score analysis for linkage detection.

### Population Genetics
Hardy-Weinberg equilibrium: p2 + 2pq + q2 = 1.
Deviations: mutation, selection, drift, migration, non-random mating.
Genetic drift: founder effect, bottleneck effect.
Natural selection: directional, stabilizing, disruptive.

### GWAS and Complex Traits
Genome-wide association studies: SNPs, Manhattan plots, p-value thresholds.
Polygenic traits: multiple loci each with small effect.
Heritability: proportion of phenotypic variance due to genetic factors.
Linkage disequilibrium: non-random association of alleles at nearby loci.

## Key Patterns



## Best Practices
- Always define dominance relationships before solving problems
- Use Punnett squares for simple crosses, probability for complex
- Check Hardy-Weinberg assumptions before applying equilibrium
- Distinguish between genotype and phenotype clearly
- Consider both nuclear and mitochondrial/chloroplast inheritance

## Common Pitfalls
| Pitfall | Fix |
|---|---|
| Confusing penetrance with expressivity | Penetrance is all-or-nothing, expressivity is degree |
| Ignoring epistasis | Check for modified ratios in dihybrid crosses |
| Applying H-W to non-equilibrium populations | Verify all 5 conditions first |
| Confusing cM with physical distance | Recombination frequency is not linear at large distances |

## Related Skills
- molecular-biology-expert
- genomics-expert
- evolutionary-biology-expert
- bioinformatics-expert