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Good now we no longer need to worry about keeping all the female or male fish alive anymore. Obviously they are having problems finding a mate to spawn if they have both parts :happy:
 

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mrmugs said:
Keep in mind that humans also have been born without certain organs or limbs, or doubles. Sometimes it's just a birth defect.
You beat me to it.

ADD ON EDIT... "just a birth defect" is a interesting statement in itself. I suppose the abnormality could be either a) due to inherited genetic deficiencies (the source of which could be DNA replication "mistakes" or from mutagens) b) the result of a teratogen on the embryo.

I guess what I'm trying to say is that it is difficult to determine where the problem began. The phrase "just a mistake" is a scapegoat used to explain something we don't understand/ haven't determined the cause of. Do you see the irony the brackets above? This begs the questions "where did these "mistakes" arise from? How did they occur? Why did they occur? etc.

Let me explain the the difference between DNA replication mistakes vs. Mutagens. If the parent fish has a malfunctioning DNA replication apparatus (Q: where did problem arise?) the offspring will inherit a) faulty "DNA rep. apparatus genes" and b) other "faulty gene(s)" (in this case, causing a hermaphrodite) because the inherited genetic info was "copied" wrong. On the other hand, a mutagen alters the offspring DNA so that the parent may be normal and produce messed up offspring. In other words, one step before a teratogen (which affects the offspring once egg and sperm have joined.)

For those who don't know, a teratogen is a substance that causes "birth defects." At different times during gestation (pregnancy) the embryo or fetus is sensitive to different insults. For example, from weeks 4-8 the the human heart is developing rapidly. If the fetus is exposed at this time to a teratogen that is known to affect heart development, the function/anatomy of the heart will be most pronounced.

Hope this made sense...as you can probably tell I study science rather than english/grammar etc LOL. It's a hard concept to wrap your head around if you don't have some understanding of genetics, cell biology and embryology. Either way, it's an interesting subject to think about.

:beerchug:
 

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bronjuan, if you get a chance there is a really good Nova (the TV show) that look at how genes can be trained on and off by the effect of chemical on the outside structure of the gene. It showed how diet and environment effect could effect the traits of the next generation. They were saying that is why we find similaritybetween grand parents and grand children, such as diabetes. The reason for the similarity between grand parents and children is that our DNA is made when the eggs and sperm are made; in the womb for egg and at about thirteen for sperm. So the chemical the gene come into contact with at that time can change the outside shape of the gene when they are made, turning them on or off. Crazy stuff!

As for the mutation thing, I heard off case that was one of the key arguments for stopping the depletion of the O3 layer. Frog in Colorado were sprouting extra limbs with surprising regularity. The first conclusion the scientist came to was increasing UV was causing the mutation as frogs are more susceptible to the rays. However, after more research it was found that the mutations were happening because of unsuccessful garter snake bites. I not 100% on the story as it was awhile ago but I think it goes like this. Either the snake were biting them during the key time when they were changing from tadpoles to frogs and the severed cells did not know what to do, so the kept on making extra appendages. Or it was that the snake had a enzyme, phage or virus that cells to split making more legs.

Cool stuff, Have fun, Jason
 

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Yeah frogs are cool because they go through, I guess you could call it, a visable embryonic-like set of changes (tadpole to adult). I can hypothesize why an injury would cause this... in a nut shell, cells rely on/communicate with neighboring cells via receptors/ligands (cell-cell signalling) and also local hormone production (paracrine signalling) where the effect is on the cells near by...(this is different than say, testosterone, runs through your whole body and has diff effects at different sites.) So I'm thinking, when the frogs were injured, this communication broke down, cells "on the cut" no longer received signal saying "stay as skin" and began forming "leg cells" just as the "normal to-be-leg cells" would be lacking this signal. A lot of this stuff requires concentration gradients etc of hormones and depending on how much hormone is present, the cell will be determined to a different fate.

Anyways,

Now that I think about it, I think gonads (like the fish in this example) is determined by the Y chromosome. Basically, if you have XX, youre the default and will always develop ovaries. Whereas in males you have XY, and the Y chromosome has genes to develop testes. I'm running into a wall now on how hermaphroditic events occur...blah I'll get back to you once I finish my reproduction block.

Oh btw, in my other post the example of where "the offspring would inherit faulty DNA replication machinery" would likely die far before being born. I just added it for completeness.
Wow, I've really hijacked this thread.
 

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When they enter fresh water, salmon usually
stop eating and live only on stored body fat. To (stomach shrinks to allow room for eggs)
save energy, they lose the slimy coating that
helps protect them, their skin becomes thick and
leathery, and they start to absorb their scales.
Some internal organs may fail on the journey.
The salmon’s appearance changes dramatically,
with males and females developing distinct
differences. They lose their silvery colour and
take on deep red, green, purple, brown and
grey colours. Their teeth become long, and they
develop a hooked jaw, which is particularly
pronounced in males. Their body shape can
change, with some species developing a distinct
hump on their back. Eggs develop in the ovaries
of females, while males develop sperm.
 

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mrmugs said:
Keep in mind that humans also have been born without certain organs or limbs, or doubles. Sometimes it's just a birth defect.
absolutely. you would be shocked to see how many humans are living today with such extremely rare mutations or congenital diseases. you can actually have a look in youtube. So, nothing wrong or weird to find out simialr issues in other non-human animals.

G
 
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