Notes for Mark Torrender re. mutations.

1) The popular idea of a "mutant" in cheap sci-fi and comics, is not the same as the biological notion of mutation. In sci-fi/horror, a mutant is a grotesque transformation of an already existing creature. In biology, it is merely the addition to, the deletion of, or replication of or alteration of some already present DNA in their progeny. Most mutations are deleterious. (They reduce the chances of the DNA being reproduced in subsequent generations). Next, come neutral and synonymous mutations. (See below). And next, come advantageous mutations. (See below below.)

2) Synonymous mutations are substitutions of DNA base-pairs that make no difference to the amino acid sequences that are specified during transcription. They are translated into identical products. See  https://en.wikipedia.org/wiki/Codon_degeneracy

3) Although "advantageous" mutations are far less common than neutral and deleterious ones, they are the most significant mutations in explaining and understanding evolution. This is because of the phenomenon of natural selection. Natural selection is a mere metaphor. All it means is that any heritable variations that increase their own chances of getting reproduced naturally increase in frequency in a population, generation upon generation. As Thomas Henry Huxley (Darwin's friend) said, "How stupid not to have thought of that!"

4) Darwin knew that there were problems with what he called "blending inheritance." Why didn't progeny all turn out the same eventually? Why, for example, do we still have black cats and tabby cats? Why aren't they all mud-coloured by now, like modelling clay in children's' classrooms?  Darwin, unfortunately, never got to hear of Mendel's work, which pointed the way to a "digital" explanation of inheritance, culminating in the work of Crick, Watson, and the lamentably unacknowledged work of Rosalind Franklyn.

5) Daniel Dennett (I believe) coined the term "the Library of Mendel". This is an imaginary library of all possible genomes or DNA sequences, which is virtually infinite, but referring back to point 3,  which ones do we expect to survive and prosper, and which ones do we expect to promptly expire?