Thread: Mutations in Genetics?

Do mutations happen at random or do they occur based on the needs of survival in the environment? That is, does the environment cause the genetic mutation or do tons of mutations happen randomly and get selected based on its survival value. Or perhaps the random mutation happens to be the one compatible with means for survival and over time continues surviving?


That being said, how does a species die out naturally if already equipped to survive according to its genetic code?

Mutations occur randomly.

Those who improve reproductive odds will continue to latter generations. Those who decrease reproductive succes will die off. (reproductive succes in the broadest way possible).

Like the man said. Mutations occure randomely. They are then screened by natural selection. One point that is not often mentioned is that a mutation need not immediately be an advantage to its bearer. The mutation which is currently protecting about a third of the population of Europe against HIV happened almost a thousand years ago in a viking. His decendents all bear the mutated gene and we are now finding that it confirs some immunity to HIV.

Originally Posted by Sealeaf

Like the man said. Mutations occure randomely. They are then screened by natural selection. One point that is not often mentioned is that a mutation need not immediately be an advantage to its bearer. The mutation which is currently protecting about a third of the population of Europe against HIV happened almost a thousand years ago in a viking. His decendents all bear the mutated gene and we are now finding that it confirs some immunity to HIV.

This has nothing to do with a mutation to help protect against HIV. This is biodiversity. HIV is to specific to bind to T-14 cells, and antigens that these mutants with "viking DNA" just don't have, so the virus can't find a host. It was not a selective proces due to HIV. Because this is actually a pretty recent disease where 100 years ago, just some afrikan tribes suffered from, due to the eating of ape meat.

Originally Posted by Zwolver

Originally Posted by Sealeaf

Like the man said. Mutations occure randomely. They are then screened by natural selection. One point that is not often mentioned is that a mutation need not immediately be an advantage to its bearer. The mutation which is currently protecting about a third of the population of Europe against HIV happened almost a thousand years ago in a viking. His decendents all bear the mutated gene and we are now finding that it confirs some immunity to HIV.

This has nothing to do with a mutation to help protect against HIV. This is biodiversity. HIV is to specific to bind to T-14 cells, and antigens that these mutants with "viking DNA" just don't have, so the virus can't find a host. It was not a selective proces due to HIV. Because this is actually a pretty recent disease where 100 years ago, just some afrikan tribes suffered from, due to the eating of ape meat.

I think you are saying the same thing. This (protective) allele exists because of diversity. How did that diversity come about? Because of a mutation at some point in the past. At that time it was neutral; now it is beneficial.

(There is a theory that this mutation/variation was multiplied in some populations because it also protected against bubonic plague. But it think that is now doubted.)

Do mutations happen at random or do they occur based on the needs of survival in the environment?

In some organisms - maybe quite a few - it's both: stresses and damages from a changed environment, one that the organism no longer fits well, can lead to responses both pyhsiological and behavioral that increase the rate of mutation and/or decrease the efficiency of repair.

And this can be set up - is, in some bacteria, maybe others - to be more of a factor in some stretches of the genetic code than in the rest. The malarial organism is one that seems to be set up to allow and propagate mutations along some stretches of its code, the stretches that code for such things as the proteins typically used by human immune systems to identify intruders.

The mutations themselves are still random, in the sense that no individual one is a caused response to a specific pressure.

Random, and also imo in many cases mutation have no apparent effect, until a context makes it helpful or harmful, which means theres a truck load of subtle variations in a population even before some factor comes in for which this or that is helpful(or harmful) . If a % of the population have a Tcell mutation that makes it unlikely they develop a given disease, no one knows about it, and if a different disease spreads for which thats a risk factor that same beneficial mutation can now be (somewhat arbitrarily) labeled a genetic defect.