So, I just finished my biology 1 course and was thinking about different enzyme deficiencies. I was pondering if the over the macro expression of the human genome we are becoming more or less intolerant to lactose sugar. I guess my question is if the allele is being selected for lactose breakdown or if through natural selection it is not being selected for. It seems that are species is one of only a few species (that I know of) which have the ability to correctly digest lactose after weening. If lactase is not produced after this weening in some individuals, then maybe the genome as a whole might not be selecting for lactase expression. A definite caveat to this though is that for a small part of our existence we have been culturing and refining foods which require lactase to digest, so maybe the genome is actually selecting for lactase production and the ones who are lactose intolerant have not received that allele just yet. What do you think?

uuummm wow.

Welcome to Mingle..

Natural selection gave Africans and other equatorial residents an infinite amount of diversity in protein and plant based carbs. The same natural selection which would reduce the skin pigment to heighten production of light based vitamin D would also place children in a position to better survive by an increased ability to use milk as a primary food source. Ice age dwellers may go months without fruit or vegetable matter relying only on a few sources of meat and fat. Expanded use of mother's milk would be a major selective plus.

Caucasians are rather unique in there tolerance of lactose.

You are proposing, OP, that there is a selecting of those of the population that have the allele for lactase.

This is hard to prove. You could only say this with assurance if there is statistical significance for the lactose intolerant to not reproduce. I don't know if that has been established.

Even if statistical evidence exists, it is hard to prove that it's the lactase incopmetence that causes the lack of successful reproduction. It could be any number of other things, that are strictly or loosely co-occuring with lactose intolerance, and it's the other thing that is being selected out. Even harder to prove.

It is hard to imagine that lactose intolerance alone will select a sub-group out and make it die out. For one thing, many people become lactose intolerant later in their lives, at an age which is well into their span of sexual maturity. For another thing, there are much more severely disabling or survival-hindering diseases, the sufferers of which will happily create issues.

So the proposal you make is hard to prove empirically, impossible to prove theoretice, and therefore it's philosophy, since it tries to solve a phenomenology problem with speculative methods.

wow,

I really did not intend to ruffle anyones feathers with this post. My reason for opening this discussion was to get some creative juices flowing and have failed in that. I did not intend to propose a solution or to say "one thing is thus, and another thing is not." I was simply looking at friends and family and asking what one might see if he/she were able to extrapolate a curve over all of mans existence to a particular allele for the lactase enzyme. Is there a trend of humans selecting for lactase or not. When a colleague proposes a question, in my experience, it is intended to start an open ended discussion, which might lead to some new knowledge on both partie's side.

Hey!! That's great. I did not mean to give the air out that my "feathers were ruffled". Indeed your post did start my creative juices flowing. I liked your question, and I gave my best shot to answer it. My answer was thought out, it was not amere string of haphazarly put-together thoughts.

If the answer you were looking for was not there, sorry, like you said, the discussion was creative, and one thing of "creative" is that you don't know what to expect from a creative discussion. In fact, I feel your mission did not fail, but really was successful, if your goal was to get the creative juices flowing.

In your second post you talk about plotting a graph over humankind and extrapolating from that curve, vis-a-vis lactose intolerance.

Yes, that's a good idea. You can start by deciding what should be on the X axis, (domain) and how each X value should see a corresponding value Y, which, when strung together, would yield a curve.

I think that's your first task. You must decide what's on the X, and how Y points related to each X.

This is applicable to all "curves" on Cartesian 2-dimensional co-ordinate systems, and you are proposing somethign like that, so do it!! Don't let anyone, including us, stop you from it.

If this was not in my first reply, that's so because you did not ask for it in your original post.

And thanks for a good question, a good, creative-juices sqeezer.

Keep up the good work.

Don't let negativity bother you -- we philosopher are an argumentative bunch, just like trial lawyers. The only, and I say the ONLY difference is that trial lawyers make a lot of money, and you'll need one when in trouble with the law; whereas philosophers are poor, can't make any money with philosophy, and nobody in his right mind would ever need philosophical help, no matter how much in trouble they are.

Other than that, lawyers and philosophers are both clear, organized thinkers, are creative in their thought processes, are both excellent with the language, and both are argumentative. Both will always look for the exception from the rule, both will value reason and logic above all else. One more little difference: Philosophers, when they debate, try to vict over their debate partners only with logic. Lawyers, trial lawyers, can use methods of arguments other then clear, unadulterated logic, and they don't have to be ashamed of it or avoid using them. Their purpose is to convince a judge, and a jury if there is one; these are humans, who understand logic other than the mathematical or philosophical ones. Humans who make juries understand emotional logic and spiritual logic as well.

So please, OP, don't be discouraged if you don't find explicit support and work for your thesis by others. It is a fair field, each player is a one-man team, and we're here to have fun. Your input is valued, like everyone else's, and please don't expect us to do any work for you, mental work, but other than that, please consider us your comerades, and if we argumentative, then that's nothing personal about you or your values or points, it's just that we are philosophers. If you need help in school project, we can help, but not on this venue, and probably not for free, but I can't speak for the others.