Guppies with a genetic timebomb?

Yup. Genetic timebomb.
Baaasically, last year my mum got some adult, pregnant guppys from my godfather, who then proceeded to drop babies, about 15 of which survived. Once they were old enough, I nabbed three (before they developed obvious sexual differences), three when to my boyfriends mother, and the rest stayed in my mothers tank. They're (or would be) about 6-7 months old by now, and my boyfriends mothers dropped babies the other month.
Now, onto the puzzling bit.
The beginning of the year, we found one dead against my mums filter (female), put it to the fish habit of dropping dead for no apparent reason, and got on with it. Another followed a few weeks later, dead on a plant (male) Then we lost another, a few weeks later. This female had always been stupidly skinny, like a pencil, but never underfed. Then, the other day, we found another dead one (male) under my mums filter box. Yesterday, we lost the surviving old female, but thyat was to be expected, she was ooolllldd.
So anyway, all these deaths, so close together got my suspecting something was wrong in my mums tank.
And then, all of a sudden, one of the guppies and my tank keeled over for absolutely no reason. My nicest one as well. Was fine this morning, checked them after a long sleep (I was ill last night) and found it floating around, fins stuck out like it just froze whilst swimming. It's tail was frayed, from being perfect, but that was probably be others thinking Mmm~ Food.
So, to summarize, nearly a whole generation of guppies have all died at about the same time, one of which was within a completely separate tank to the rest. Is it possible for them to have inherited a genetic timebomb, which killed them off at around the same time? Could the dead ones have come from one guppy, and the surviving ones come from the other one perhaps? (both mothers deceased)

I hope you can see sense in this, it's really bugging me :P

Definately a thread for the guppy fans out there, I've never kept them.
J

Aha, my mum used to like them, she hates them now, because all they do is pester the females and eat each others tails D:
But to add, one of her older neon tetras kicked it today, coincidence? About 1 year old :P Theres absolutely nothing visible wrong or different with them, behavior and appearance wise.

I must admit i feel sorry for the female guppy....sometime they are hounded to death by randy male's i mean overly randy male's lol...
Painfull to watch sometime's hence why i wouldnt keep them....

Yeah, it's horrible! The three I stole eventually grew up to be 2 males and 1 female, and they pestered the poor girl so much that I moved her into another tank with the fantail and glowlights

thats happend to me before, it was the night before i was going to sell 30 of my endlers to the local fish shop. Woke up next day and what do you know all 30 of them dead. The females were fine, they were happy to be swimming around without being harassed. it was weird. about a year down the track and not one more has died it was like they all planed it.

:O Mass endler suicide!