General Genetics

Did you know that 40% of your genes are the same as those in a cucumber? Does this make me a 40% cannibal if I eat cucumber?

Today I heard Professor Jack Heinemann from the Molecular Biology Department of the University of Canterbury give a brilliant presentation which was an introduction to genetics and genetic determinism. While there was an awful lot to take in he was a superb speaker with good illustrations, humorous anecdotes, and not one “um”.

The study of genetics started in 1863 with Gregor Mendel who studied peas and showed that traits could be passed on through inheritance. We learned that phenotypes are observable physical traits, which are the result of the interaction of the genes, environmental factors, and random variations. Genetics relies on incest to breed a pure line within a family of organisms. Not all genes are DNA. Mendel’s patterns can be explained through Meiosis, which is reproduction through the joining of female and male.

Genetic determinism is the origin of molecular biology and is the idea that most human characteristics, physical and mental, are determined at conception. This idea has led to some strange outcomes, such as eugenics and social control, as it can appeal to our prejudices in a way that has nothing to do with the data. Jack warned that it can lead to people being preyed on by organisations that offer to sequence your DNA, such as Ancestry.com.

Simple traits are easy to follow, but complex traits are more complicated and we may be influenced by underlying assumptions.

When asked about drugs such as puberty blockers Jack observed that denying a genetic basis can put people at risk. He pointed out that chemicals can affect our development, and in recent decades they have mainly not been evaluated. It’s too late now to measure the effect of some chemicals because they are so widespread and we no longer have a control group.

Questioned about the spread of false information e.g. about Covid, Jack said that after World War II governments gave drug discovery and development up to the commercial sector, and we are always going to be vulnerable to people who want to mislead us. There is limited control on those who have concentrated power, and there is a danger that science is turning into a faith-based organisation, e.g. “trust us – we’re scientists.” All this information gives food for much thought.

Is it a worry that a number
of human cells match the cucumber?