The Oxford English Dictionary records Wilhelm Johannsen writing in 1911 in American Naturalist:
“I have proposed the terms ‘gene’ and ‘genotype’ ... to be used in the science of genetics. The ‘gene’ is nothing but a very applicable little word, easily combined with others, and hence it may be useful as an expression for the ‘unit-factors’, ‘elements’ or ‘allelomorphs’ in the gametes, demonstrated by modern Mendelian researches.”
Less than 20 years ago I was not too certain whether genes had chromosomes or chromosomes had genes, but have since made determined efforts to understand the field better. One aspect which is difficult to get a grip on (& sometimes, alarmingly, seems not altogether clear even to practitioners of various branches of genetics) is that of what kind of variation we are talking about: is it at the level of the individual bases, (A,C,G,T) … through genes, phenotypes & right up to geographical or between-population variations, or the difference between animals, plants & humans, or ...
I was intrigued therefore to read an article by Professor AAW Hubrecht in the Contemporary Review of June 1909, under the title of Darwinism and Wallaceism*:
“From the first … it was evident to Darwin that the artificial selection exercised by man was far from being under his full control …. Breeders did not always know what they were actually working with & there was confusion whenever the attempt was made to draw hard & fast lines between species, varieties, races, types, kinds, sports & crossings.”
And when we can read in more modern times (2006) that
“Although the composition of DNA & the genes it carries is reasonably uniform & stable in the same individual, there is wide variation over time & between different body tissues in the level of protein production by any particular gene”
or of
“gene expression data … comprising several measures of the expression of many thousands of genes in two or more groups of individuals”
it is clear that even the full genome of any individual cannot provide the key to unlock the secret of their life – past, present or future
*This was a response to an earlier exchange, part of which can be found in Wallace Collection - Darwinism versus Wallaceism
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