Write a brief note on chromosomal mutations and gene mutations

Explanation

Theory of mutation was proposed bỹ Hugo de Varies, who coined the term mutation.
Mutations are sudden, random inheritable changes that occur in organisms. Húgo de Varies observed this phenomenon in the evening primrose plant Oenothera lamarckiana, which shows different forms like,
O.revistylis - with small style.
O. levifolia with smooth leaves..
O. gigas - with the giant form.
O. nanella - with dwarf form
These characters are inherited to the progeny.
Darwin called mutations as sports of nature or saltations.
Bateson called them as discontinuous variations
Salient features of mutation theory :
Mutations occur from time to time in naturally breeding population.
Mutants differ from their parents.
Mutationis are inheritable,
Mutations occur in any direction i.e., they are random.
They are discontinuous and not accumulated over generations.
They are full-fledged and so there are no intermediate forms.
They are subjected to natural selection.