Why your college genetics class sucks

A college lecture hall — just look at all the excited faces.
From greatcollegeadvice.com

Although I am now a practicing geneticist, I hated genetics when I was in school.  My Genetics 101 course followed the same syllabus that colleges all around the country use, a historical outline that emphasizes discovery — the discovery of phenotypic variation (Mendel and his wrinkled peas), the discovery of DNA and its structure (Watson and Crick and Franklin), the discovery of genetic mutation (in Mendel’s case, a disruptive insertion within the rugosus gene).  We’re presented a top-down view of genetics from phenotype (wrinkled versus smooth) to genotype (mutation in rugosus) that should compel us to ask “Why?”  But before the bell ever rings on that first day, most students already know that the answer to this question.  “Why?” lies somewhere in our DNA and we don’t want to discover it all over again.  And, unfortunately, this historical top-down approach doesn’t increase our understanding of genes in the age of whole-genome sequencing.  In response to this problem,  PLoS Biology published the short article, “Why Do We Have to Learn This Stuff?  A New Genetics for 21st Century Students.”  In it, Dr. Rosemary Redfield describes the problems of current genetic courses and offers her own remedies.

Besides being boring, Redfield also points out that most college genetics courses still emphasize methods and skills that are no longer relevant.  Anyone remember learning about the Avery-MacLeod-McCarty experiment and having to analyze their results to show that DNA is the genetic material?  What about a three-factor cross or analyzing phenotypic ratios among a set of hybrid progeny?  Historically, these methods helped us discover fundamental concepts about how genes work; but, practically, they are rarely, if ever, used.  In the last ten years alone, the methods geneticists use to collect and analyze data has changed dramatically.  How will learning about three-factor crosses today help students practice and understand genetics tomorrow?

Redfield’s solution is a new genetics course that’s not structured on history but our modern understanding of genetics and biology.  After all, we cloned Dolly over 16 years ago and ingrained genes and genomes into our collective consciousness ever since.  It’s time our courses started by accepting this basic fact, and leave Mendel and his peas to an interesting (and, by the way, unusual) case study.  Redfield outlines a syllabus that emphasizes the role of genetics in the modern era starting at the bottom-up (or, to make it easier, from rugosus to those wrinkly seeds).  The course starts with genomes and DNA and then moves on to mutations, genes,  and gene expression; it then covers genetic assortment, mitosis, and linkage; and finally explores how these mechanisms collectively produces phenotypic differences or disease.  The course works just like your genes do — from the bottom on up — and should better equip our students to understand genetics in the 21st century.

I think Redfield’s syllabus is a great idea and know a few professors that have already started using it or something similar.  The top-down approach just doesn’t work in a society that already has a grip on the basic nuts and bolts.  And it doesn’t help inform them about problems they’re likely to face, like genetic screening or whole genome sequencing. Redfield’s syllabus (below) is a great start to a 21st century approach to biology and genetics.  What do you think?

Suggested Syllabus for a 21st Century Genetics Course

  • Personal genomics
  • Natural genetic variation in populations (humans and others)
  • Structure and function of genes and chromosomes
  • Genetic variation arises by mutation
  • Genetic variation and evolution (selection for function, phylogeny, homologs, gene families)
  • How genes affect phenotypes: pathways, regulatory interactions, heterozygosity, dominance effects (several classes)
  • Genetic variation also arises by chromosome reassortment and homologous recombination
  • Mitosis and meiosis: mechanisms and genetic consequences (several classes)
  • Mating: mechanisms and genetic consequences
  • Linkage and sex linkage
  • Genetic analysis: investigating gene action using inheritance of simple (“Mendelian”) alleles and phenotypes in crosses and pedigrees (several classes)
  • Organelle genetics
  • Epigenetic inheritance
  • Genome structure, function and evolution; causes and consequences of chromosomal changes (several classes)
  • Phenotypic effects of natural genetic differences, heritability
  • Genome-wide association studies and related studies linking genes to phenotypes (several classes)
  • Genetics of cancer; inheritance of alleles affecting risk

3 thoughts on “Why your college genetics class sucks

  1. I’m happy to say that the genetics course I TA is headed in the direction of the syllabus described above. I will also note that the students do seem to enjoy the second half of the course better, after we have moved on from the basics. However, what’s a little surprising and disheartening, is how many students actually don’t have a grasp of the basics. I get students every year who don’t know how to set up a Punnett Square for a dihybrid cross correctly. But I definitely think we need to bring genetics classes into the 21st century.

    • Don’t know how to set up a Punnett’s Square . . . sigh.
      But Redfield comments on this very (sad) phenomenon. She argues that by starting with phenotypes first, we’re forced to treat alleles as abstract concepts unconnected to any notion of DNA (which they were — when Mendel discovered them). By by starting from the bottom-up, we can introduce DNA and mutation and chromosomes first. That way, by the time we get to Punnett’s Squares, students should know that the alleles represent two nucleotides that are found on two homologous chromosomes. Hopefully, that will better prepare students to set up those squares.

      PS — I still use Punnett’s Squares sometimes. It’s true.

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