Why can't you buy guppy females at petland?
- Thread starter SamNYC
- Start date
First, a few tanks doesn't "prove" much of anything, the sample size is still way way WAY too small. Nowhere near large enough to draw a conclusion about the genetic tendencies of guppies as a species.
What's more, you can't sex them at birth; What is the survival rate? The survival rates of each sex differs depending on environmental changes(which I posted a reference to earlier in this thread). The authors of that paper noted that they were able to observe ratios that differed from 50/50, though not significant. They concluded that this was likely to do with the survival rates of each sex.
As I've said, this isn't the kind of thing you can determine in a home aquarium. Does anyone have anything that's been put together by a lab and published, aside from what I posted? It says, though this isn't the focus of the paper, that 50/50 is the norm. Survival rates might not match that, and because it's random you're never guaranteed that ratio.
Want to try out a random walk for yourself? Grab your jar of pennies, take out 40 of them, and scatter them on the floor from high-above so they flip around. Do you have
exactly 20 heads and 20 tails? I doubt it.
Joe, i would stop drinking your tapwater if i were you... look what it's doing to your fish..:laugh:
OK. From research I think I have a handle on this.
Most male guppies are XY, females XX, as in humans. Naturally that means half the sperm are X and half Y, which is why one would expect a 50:50 ratio of males and females.
Normally this is what happens.
However, guppy sex determination is slightly complicated by the fact that there are other sex markers dotted on the non-sex chromosomes. Normally these are balanced, and so sex is determined by the X and Y chromosomes. But not always. In some strains there are an excess of male markers which can result in exceptional XX males. Mate an XX male with an XX female and you get all XX offspring - most of which will be female, but a few of which will be, like their fathers, exceptional XX males. Voila - a skewed sex ratio in some strains.
The article I linked to on the previous page points out there's more to it than that -my theory earlier that some males are weak in some strains is borne out by their mention of accumulation of deleterious Y alleles, so even normal XY/XX crosses can result in skewed ratios where inbreeding has weakened the Y chromosome.
Most male guppies are XY, females XX, as in humans. Naturally that means half the sperm are X and half Y, which is why one would expect a 50:50 ratio of males and females.
Normally this is what happens.
However, guppy sex determination is slightly complicated by the fact that there are other sex markers dotted on the non-sex chromosomes. Normally these are balanced, and so sex is determined by the X and Y chromosomes. But not always. In some strains there are an excess of male markers which can result in exceptional XX males. Mate an XX male with an XX female and you get all XX offspring - most of which will be female, but a few of which will be, like their fathers, exceptional XX males. Voila - a skewed sex ratio in some strains.
The article I linked to on the previous page points out there's more to it than that -my theory earlier that some males are weak in some strains is borne out by their mention of accumulation of deleterious Y alleles, so even normal XY/XX crosses can result in skewed ratios where inbreeding has weakened the Y chromosome.
ok.. i see breeding statistics, but nothing to support hermaphroditic or full on gender changing abilities.
You should make friends with the guys that work there and they will sell you anything you want, try the store on 23rd or 14th.
There is also Petco on 86th, but I would watch what I buy there.
TRY http://www.newworldaquarium.com/freshwater_fish.html
There is also a nice place on Canal st, west wide
good luck
There is also Petco on 86th, but I would watch what I buy there.
TRY http://www.newworldaquarium.com/freshwater_fish.html
There is also a nice place on Canal st, west wide
good luck
