The book doesn’t assume any knowledge of genetics, and aims to instruct the read about that, skipping over many details deemed less necessary for understanding the point of the book – that there is no “objective” of evolution for a species, and that the “selfishness” of genes drives evolution as a necessity, without any entity “wanting” evolution to happen.
I think Dawkins could convey his point across more easily if he defined his terms (which seem a bit different from the mainstream nomenclature) from the start. My understanding of his simplified terminology so far (before reading up in Wikipedia) is:
nucleotide = the basic bit of genetic information; can be one of four kinds: Adenine, Cytosine, Guanine, Thymine
cistron = a sequence of nucleotides, clearly marked with a “start” marker and a “stop” marker
chromosome = the longest sequence of nucleotides
gene = a sequence of nucleotides of arbitrary length, which may span cistrons partially
Genes, not alone, but combined with the environment, determine the characteristics of an organism. My own analogy for this is: imagine you have a sequence of directions like “3, L, 2, R, 4, L, 1, R”, meaning take the 3rd left, the 2nd right, the 4th left etc. Without a set of roads (the environment) and a starting point, this sequence doesn’t lead to anywhere specific.
The understanding I get from these two chapters seems to have some holes. I need to see if a deeper understanding of the basics is necessary for grasping the book fully. It probably is, though, for grasping life extension.