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>> LQ 3.1 How has the study of genetic inheritance changed in the last century?

There is a long history associated with the nature versus nurture controversy based on the idea that certain human attributes will be determined by our genes (nature) or by our experiences in our environment (nurture). To begin to understand the sometimes shocking history of genetics research, read Journey of Research: The History of Research on Genetics.

Journey of Research: The History of Research on Genetics

The modern study of genetics began in 1866 when Gregor Mendel, a Central European scientist and monk, published a paper outlining a number of principles that guide the transmission of genetic information from one generation to another. These principles, which Mendel discovered by studying the way characteristics of pea plants pass from one generation to the next, came to be known as Mendelian inheritance. Although Mendel could describe the patterns of transmission, he did not know about genes and it was not until 1900 that the significance of his work was recognized (Gayon, 2016).

At about this same time, the English psychologist and anthropologist Francis Galton concluded that certain desirable traits could be bred into human beings, while undesirable ones could be bred out. This process, which Galton called eugenics, would require promoting reproduction by “superior” human beings and inhibiting reproduction by “inferior” ones. The idea was so influential that, beginning in 1907, 30 states in the United States passed laws allowing the forced sterilization of about 60,000 people considered “criminals, idiots, rapists, and imbeciles” (Watson, 2003, p. 27). (The terms idiot and imbecile in those days indicated levels of performance on IQ tests.) As the Nazis came to power in Germany in the 1930s, they enthusiastically adopted a policy that embraced eugenics. They began with sterilization but then moved to mass murder of all those they deemed unfit to reproduce for a multitude of reasons. This came to include annihilation of entire ethnic groups in the service of creating a pure “Aryan race” (Watson, 2003).

As a result of the eugenics movement and its excesses, genetics research came to be seen as suspect. It was not until the 1950s that the American biologist James Watson and British molecular biologist Francis Crick discovered the basic secrets of genetic structure and function. With their findings, scientists were able to understand the exact process that underlies the genetic transmission first described by Mendel almost 100 years earlier. In 1990, with James Watson as its first director, the Human Genome Project undertook the ambitious goal of mapping all the human genes (National Human Genome Research Institute [NHGRI], 2012a). In 2003, 50 years after Watson and Crick’s discovery, the map of the human genome was completed (NHGRI, 2016a).

Research on the human genome took another step forward in 2005 when a new technique, called genome-wide association, was developed. With this technique, instead of studying particular genes believed to be responsible for a particular disorder or trait, researchers can now study the whole genome at once to identify the relevant genes (Hu, 2013). Developments in the study of the human genome are occurring rapidly, yet much work remains to make the connections between specific genes and most human traits and behaviors (Plomin, 2013).

Genome-wide association: A technique that allows scientists to examine the whole human genome at once.

Genetics research. This scientist is using a technique that separates fragments of DNA by size and shows them on a gel sheet.

Andrew Brookes via Getty Images