Australasian Science: Australia's authority on science since 1938

The Evolving Story of Heredity

A female neriid fly (bottom right) lays eggs on rotten tree bark while her mate fights off an interloper. Credit: Russell Bonduriansky

A female neriid fly (bottom right) lays eggs on rotten tree bark while her mate fights off an interloper. Credit: Russell Bonduriansky

By Angela Crean & Russell Bonduriansky

Biologists are discovering that there is a lot more to heredity than genes. In the latest twist, it turns out that offspring size in an Australian fly species can be determined by the diet of its mother’s previous mating partner.

The full text of this article can be purchased from Informit.

As evolutionary biologists, we are interested in variability. What causes similarities and differences among individuals? Where does this variation come from? How is variation transmitted across generations?

According to the textbooks, these questions were answered with the discovery of Mendel’s laws, genetic inheritance and DNA. But despite having the technology to sequence entire genomes, we are still faced with “missing heritability”, and discoveries made in recent years have greatly complicated the picture. Simply put, 21st century biologists are discovering that there is a lot more to heredity than genes.

Contrary to popular belief, the path of scientific progress rarely resembles a straight line. More often it twists and turns, and sometimes doubles back on itself like a meandering stream.

In the 19th century, the most widely-accepted theory of inheritance –commonly referred to as Lamarckian inheritance after the French naturalist Jean-Baptiste Lamarck – was the idea that features acquired throughout an individual’s lifetime can be passed to offspring. For example, Lamarckians proposed that giraffes have such long necks because giraffe ancestors stretched their necks to reach the tasty leaves on the highest branches, and then passed on their stretched necks to their offspring. This sounds ridiculous to our modern ears, because the inheritance...

The full text of this article can be purchased from Informit.