genetic engineering and fish

[Panasonic]

i was having a discussion the other day, after listening to a radio station talk back show

they were comparing children of today that are taller, faster and in some cases larger in build than any of us have ever been.
the comment was made that maybe with all the genetically engineered food we are eating it is affecting growth rates.

now that comment makes me wonder!!!
with human interaction affecting our waterway, with sewarage and waste disposal could it be possible if
that happens to humans,who are eating that food, then is it possible that fish as a food chain eater could experience the same ??

[Owen]

Increases in the size of kids due to food could be related to hormones fed to our beef and chickens or the better vitamin intake than previous years.
Though I rather think with the level of obesity around today that much of the increase in size is in diameter and due to increased fat intake :(
If it were from hormones, I rather doubt that runoff of sewerage would have sufficient remaining levels to increase the size of fish.

Love to here form someone qualified to comment though!

cheers,
Owen

[CHRIS_aka_GWH]

the evolution of humans has been showing a measureable increase in size for some time (centuries). Take a trip to Cook's cottage in Melbourne - they were small dudes.

Learned thought fall along the lines of ...

an increased potential of genetic stock due to the mixing of races - we are seeing the best of the best - some of the best being trimmed thru "survival of the fittest" such as the negroids of North America & famine ravaged Africa. We are seeing the result of these incredibly hardy genes mix with the genes of the dominators, the tribes of europe & the tribes that dominated them from asia.

this genetic stock has found a point in the human communities development were the environment is still favourable & controllable, food is plentiful & we have a reasonable control of debilitating diseases.

We have the capacity to reach our potential & life is still getting easier ...
eg more people have a/c today than 10yrs ago.

We have a longer period of dedicated nursing & growth than ever before in the western world.
Kids are still at home in their 20's now.

Also, organisms grow to suit their habitable environment. That's why carp get so big in the wild.

Also, organisms in competition where resources are abundant & stressors are low will grow to their maximum potential to maximise their chance of utilising them & passing on their genetic characteristics.


Interestingly anthropologists have studied tribes in the highlands of the Asian Archipelago and noted that when competition decreases but food is still abundant & life is relatively easy then human size seems to decrease - they are unsure though whether this is due to limited genetic stock.

It is forseeable we may weaken our genetic stock by reducing the processes that eliminate the weak. As yet we haven't reach that turning point & it is a fair way off for a number of reasons that have nothing to do with GM.

There is no evidence as yet GM DNA translocates into the DNA of the beast that consumes it. Logically, it is as unlikely as you inheriting the genes of a mackeral you had for dinner last night. Digestion & the cycles of metabolism are highly erosive processes - they break big molecules into little bits then convert them chemically into something else.

The bigger concern with GM is the possibility of placing into a wild environment a species that could through competition eliminate a naturally occurring one or other species that have been proven resiliant thru time. You could end up with a currently vibrant, however reproductively sterile species incapable of adaption naturally to an ever-changing world.

there is some legitimate concern about steriods & the use of antibiotics in feed but these things are NOT doing us any favours

chris

ps ughhhhhhhhhhhhhhhh - is anyone awake - this is all i can recall off the cuff, it been a long week.
where's my beer !

[The_Walrus]

I read an article on this subject and the concensus from the learned ones was that due to easier living and plenty of food, humans are getting taller and reaching sexual maturity sooner.

Eg, around the WW1, it was very unlikely that a 12 year old female could become pregnant. Today, it's quite possible.

Mind you, the same article stated that compared to men living in the middle ages, we're weaklings as the amount of sheer physical work we do is negligible. ;D

Luc

[Gazza]

;) Qld BananaFish

[DICER]

that's a fish to avoid on the boat - it will bring you bad luck!

[DICER]

The increased growth rates observed in the youth and population of today, compared with that of earlier generations, has nothing to do with genetic engineering of the food we eat. The average height, age of sexual maturity etc.... has been increasing for a longer period of time than genetic engineering has been used to alter crops and food stuffs!

The following couple of paragraphs are from the New Scientist article:
http://www.newscientist.com/channel/being-human/mg18524891.100

Humans today are the only animals on Earth to have a teenage phase, yet we have very little idea why. Establishing exactly when adolescence first evolved and finding out what sorts of changes in our bodies and lifestyles it was associated with could help us understand its purpose.

We humans take twice as long to grow up as our nearest relatives, the great apes. Instead of developing gradually from birth to adulthood, our growth rate slows dramatically over the first three years of life, and we grow just a few centimetres a year for the next eight years or so. Then suddenly, at puberty, growth accelerates again to as much as 12 centimetres a year. Over the following three years adolescents grow an astonishing 15 per cent in both height and width. Though the teenage years are most commonly defined by raging hormones, the development of secondary sexual characteristics and attitude problems, what is unique in humans is this sudden and rapid increase in body size following a long period of very slow growth. No other primate has a skeletal growth spurt like this so late in life. Why do we?

Until recently, the dominant explanation was that physical growth is delayed by our need to grow large brains and to learn all the complex behaviour patterns associated with humanity - speaking, social interaction and so on. While such behaviour is still developing, humans cannot easily fend for themselves, so it is best to stay small and look youthful. That way you do not eat too much, and your parents and other members of the social group are motivated to continue looking after you. What's more, studies of mammals show a strong relationship between brain size and the rate of development, with larger-brained animals taking longer to reach adulthood. Humans are at the far end of this spectrum.

It would appear that in recent times that this balance is changing, perhaps because of lifestyles.....

The theories surrounding adolesence:

1) adolescence evolved as an integral part of efficient upright locomotion and to accomodate large brains
2) adolescence in our species could be to precisely time the success of the first reproductive effort - girls after they look sexually mature to ensure success and maintenance of the offspring, while boys will look immature well into their teens! It makes sense with cultural, social and sexual maturity.

Other things:

Neanderthals died young - about 25 years old—primarily because of the harsh conditions they had to endure in glacial Europe. Under pressure from this high mortality, they evolved to grow up quicker than their immediate ancestors - maturity at about 15.

About 15 million guys from Asian decent have inherited the same Y chromosome as Ghengis Khan.

3 million guys from Irish decent inherited the same Y chromosome from warlord known as "Niall of the Nine Hostages".

The reason why cane toads and carp grow very big outside their natural environment is due to the "founder effect" and a reduction in mortality due to drastically reduced disease and environmental pressure.