What is the difference between "cistron" and "gene"?

Question

I'm asking after reading the cognate wikipedia.en article on "cistron". I am still not sure about the difference between the two terms. To me it seems valid to picture a "cistron" as the genome wide set of a specific gene's alleles ? Thus if all copies of a gene bear recessive mutations all generating the same phenotypic trait (not necessarily the same mutation) no complementation is observed in a cis-trans test?

Answer 1

This is what I got from the Wikipedia page:

Imagine three distinct situations (I would suggest drawing these out).

1. "Gene X" - there is a mutation on both chromosomes at the same location (position X), garnering a mutant X (a homologous, trans- configuration).
2. "Gene Y" - there is a mutation on both chromosomes at a location different than the previous (position Y), but still the same location on each chromosome, garnering another mutant; mutant Y. (This is another homologous, trans- configuration, distinct from the first.)
3. "Cistron" - there is a mutation at position X on one chromosome, and a mutation at position Y on the other chromosome (i.e., a cis- configuration). This produces a mutant that could be distinct from the previous (but might not necessarily be - it's just not wild type). Note: there is an inverse arrangement.