Population genetics

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Population genetics is the study of allele distribution, transmission, and change in frequency within a population. Because mathematical models of population genetics rely on the effects of the major evolutionary forces (natural selection, genetic drift, random mutation, and gene flow)[1][2][3][4] on the behavior of alleles within populations over time, population genetics forms one of the cornerstones of the modern evolutionary synthesis that is, the current scientific understanding of the theory of evolution[5].

As a biological discipline, the foundation of population genetics is often considered to be dated to the early 1920s to early 1930s, when scientists such as J.B.S. Haldane, Sewall Wright, and R.A. Fisher applied previous work in genetic inheritance by investigators such as Thomas Hunt Morgan to quantitative models of allele behavior in populations such as the Hardy-Weinberg principle. With modern advances in molecular biology, such as molecular cloning, the polymerase chain reaction, DNA fingerprinting, and the completion of the human genome project, population genetics has come to occupy a central role in biomedical research (where it has led to numerous life-saving discoveries in the past couple decades), ecology, evolutionary biology, and even seemingly distantly-related fields such as animal husbandry, epidemiology, paleoanthropology[6], and archaeology[7].

Applications

The most commonly discussed application of population genetics is in medical research where genetic techniques are used to identify novel alleles and discover previously unknown genes associated with human diseases. The majority of this research takes the form of large-scale reverse genetic studies combining gene mapping, various modern molecular biology techniques, and translational animal models[8] to characterize the correlation between any newly-discovered alleles and the phenotype of interest to the researchers. Such research into genotype/phenotype correlations has profoundly contributed to the modern understanding of biochemical pathways, developmental processes, and human disease[9].

Human population genetics research has also led to many practical applications outside of the laboratory, notably the foundation of the fields of molecular medicine and genetic counselling. Together with recent advances in biochemistry and organic chemistry, population genetics has contributed (through studies such as those described in the previous paragraph) to a much more detailed understanding of hundreds of biochemical pathways; allowing for scores of revolutionary advances in drug development and clinical therapeutics[10].

Beyond medical applications, population genetics has greatly influenced the modern understanding of the theory of evolution, where it combines with modern developmental biology (see also: Evo-Devo)[11], cell biology, genetics, molecular biology, and ecology to yield highly predictable (but still incomplete) models for the complex interactions between genotype, phenotype, environment, and reproductive fitness that drive evolutionary change over time. In this application, population genetics bridges the gap between the observational (sometimes less accurately referred to as "historical") fields of ecology and paleontology, and the more operational (laboratory-based) fields of molecular biology and genetics. As these fields advance, and the current understanding of population genetics improves, scientists are gaining a better understanding of the history of life and the mechanisms underlying evolutionary change.

Other, less well-known, applications include animal husbandry and agriculture, where principles of population genetics have been applied to increase the effectiveness of selective breeding programs in domesticated animals (notably cattle) and crops; thus increasing the efficiency of modern food production. While this is a relatively new application, it has already yielded many promising results (e.g. drought-resistant strains of rice and corn) and will undoubtedly yield many more promising results in the years and decades to come.[12]

References

  1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3108256/pdf/nihms-123414.pdf?tool=pmcentrez
  2. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3205605/pdf/evr093.pdf?tool=pmcentrez
  3. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2728855/pdf/GEN18241141.pdf?tool=pmcentrez
  4. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2871823/pdf/rstb20090317.pdf?tool=pmcentrez
  5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2871823/pdf/rstb20090317.pdf?tool=pmcentrez
  6. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2752555/pdf/zpq16057.pdf?tool=pmcentrez
  7. Stern (2011). Evolution, Development, and the Predictable Genome.
  8. Gilbert (2006). Developmental Biology.
  9. Strachan and Read (2004). Human Molecular Genetics.
  10. Strachan and Read (2004). Human Molecular Genetics.
  11. Carrol (2004). Endless Forms Most Beautiful.
  12. Stern (2011). Evolution, Development, and the Predictable Genome.
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