What you have here is I think, a definite possibility.
I don't think there can be much argument about the fact that all LIFE, in all its manifest forms and unlikely locations, originates in a bacterial form;
I will go further and suggest that:
Every generational nuance in homo-saps, now an acknowledged feature of our strange 'sea changes'- generation X-,etc; is determined by those periodic scourges that we refer to as 'asian flu' etc...., most originating from some as yet unidentified point in central asia.
But..., but while accepting a 'bacterial' mutation for generational change within the human species..., I will still maintain that major modifications within a species are the result of changing constellationary allignments; and that mutational changes that trigger a change of species..., are most probably the result of 'possibly' controlled cosmic storms from within our own or other galaxies.