A Problem for Darwin? Doesn't blending inheritance wipe out variation?

URL: https://barryhisblog.blogspot.com/p/a-problem-for-darwin.html

Darwin had a problem. A puzzle. And as ever the open, honest and fearless intellectual he was, he did not shy away from describing it.

He had noticed that variations in the offspring occur when creatures reproduce, and he saw that artificial selection by humans could make radical changes to the offspring over the generations. Selective breeding. Maybe, he thought, something like this selection could happen in nature, but he was troubled by what was called the problem of 'blending inheritance'. 

The blending inheritance problem is trying to figure out why, when variations occur, they do not get recombined in subsequent generations and diluted away in what we would now call the 'gene pool' to such an extent that natural selection could not have a chance to have an effect.

It's rather like when you mix paints. If you go on mixing more and more different colours over and over again, you always end up with a colourless muddy brown, and all variation is lost.

Darwin knew that this problem had to be resolved, and he speculated on how it might be resolved, but he never came up with an answer.

He was unaware of the work of Gregor Mendel, the Augustinian friar and abbot, who worked on inheritance and the regularities of its operation. Individual variations of discrete characteristics were preserved over generations without blending with those in the general population. This was 'particulate inheritance'. Quantised. Digital.

When Mendel's work was dug up from relative obscurity, the combination of Darwin's and Mendel's work became known as the 'modern synthesis'. The hunt was on for how it worked, eventually resulting in the findings of Franklin, Crick and Watson on DNA, a spectacular vindication of Darwin and Mendel's ideas.

See https://www.theguardian.com/books/2003/feb/08/peopleinscience.evolution

Footnote:

Darwin often used a device in his writings, that of describing a potential problem and then going on to discuss how it might be resolved. It is a device often abused by creationists, such as in their infamous mined quote (essentially a lie), "To suppose that the eye...". His expression of a puzzle or a problem is quoted, but never what follows, where he will address it. See also https://barryhisblog.blogspot.com/p/quote-mining.html and https://barryhisblog.blogspot.com/p/qote-mining-or-how-to-lie.html