From Peas to Genomics and Beyond

peas

By Merry Morris

Ever wonder why your father and your paternal uncles share some of the same facial features? Is there a "family nose" that you fear your children will inherit? Such comparisons are human nature. We often notice the similarity between related individuals, but until the science of genetics developed, the mechanisms behind these observations were unknown.

A Genetics Timeline

Science historians differ as to what might be considered the first step in the genetics timeline. Here are just a few major events in the birth and development of genetics.

  • Gregor Mendel (1866): This Augustinian monk thoughtfully bred pea plants, and observed that the inheritance of certain traits followed statistical rules. His paper, published in 1866, reflected ideas like dominance and recessiveness.
  • Rediscovery of Mendel's Work (early 1900s): Mendel's work, "hidden" in a little-known journal, was rediscovered by Hugo de Vries and other scientists looking at problems similar to those Mendel described.
  • Chromosome Theory (1900-1913): This advance put forth that chromosomes carry inheritance factors and the first chromosome linkage map was created in 1913.
  • Genetic Recombination (1931): In 1931, "cross-over," the exchange of genetic material between chromosomes during meiosis -- was found in corn by Harriet Creighton and Barbara McClintock. This exchange explained many genetic changes or "mutations."
  • DNA (1944–1970): These years produced great advances with increased knowledge of DNA. In 1944, experiments by Oswald Avery implicated DNA or the "transforming principle," as the agent in bacterial transformation. The Watson-Crick double-stranded DNA model was determined in 1953.
  • Genomics and Molecular Biology (1970s and thereafter): The study of an entire genome through DNA sequencing and genetic mapping (i.e., genomics), as well as in-depth investigation of single genes, called molecular biology, allowed genetics as we know it to flourish. The first genome sequenced, a bacteriophage, led the way to the sequencing of thousands of viruses, bacteria and higher organisms. The Human Genome Project identified and produced a working map of genes in human DNA in 2003.

The Timeline Continues

Where will this timeline take us? In exciting directions to be sure: the genetic basis for behavior and psychiatric diseases, super-longevity, the expression of body shape by Hox genes, the importance of "junk DNA"... Hold on! It will be a wild ride!

Classroom Discussion

  • In what ways do you resemble your parents? Is there variation in that trait within your family?
  • Do you think acquired characteristics can be inherited? For example, if rats are trained to navigate successfully through a maze, will their offspring be good at the same task?
  • How do you think knowledge of a person's genome might affect treatment for medical conditions?