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evolution question

Please stop. The difference between "identical" and "almost identical" is not pedantic at all (particularly in this context: "identical twins aren't identical"... "Identical twins ARE rather ... identical!"). Why did you not think that bilby meant "almost identical"?
No, YOU stop. My writing "Identical twins are ... identical!" was obviously whimsy, intended to be slightly humorous. "Identical twins are ... similar!" would not have the same effect.

Obviously I use much different diction when I'm writing for submission to technical journals. But I don't plan on self-censoring here to cope with boring sophomoric pedantry.

As for why bilby did NOT mean "identical twins aren't almost identical" the question rather answers itself, no? Get a grip.

Would you agree that all humans are genetically "almost identical" to each other (99.9% is almost 100%)? Do you understand how important the difference is between "almost identical" and "identical" in evolution?[/I]

What??? What possible relevance does this have to a discussion of identical twins? If I indulged in sophomoric disingenuity I'd caricature this "argument" as "Neanderthal/Sapiens 99.7%. Identical twins 99.9+%. Same-same." :)

Weren't you the one who didn't understand the huge gulf between prokaryotes and eukaryotes? How does Professor Nick Lane's thinking compare with yours? Or are you just going to quibble that he begins a chapter by discussing cuckoo clocks? :)
I will just point out that I have forgotten more about genetics, and the difference between prokaryotes and eukaryotes, than you have ever know. Have a nice day.
 
Genes aren't an instruction set or a blueprint for making a phenotype, and the influences on phenotype are myriad. Sure, genetics and epigenetics are a big-ish part of that, but there's a stack of other influences, which is why identical twins aren't identical.

I think you are underestimating the influence of DNA. Many of the "non-DNA" influences are themselves a result of genes. For example the RNA editings I mentioned upthread are controlled by special RNA's and proteins which are themselves transcribed or translated from the genome.

Identical twins ARE rather ... identical! Watch the Three Identical Strangers documentary. (It's an interesting story for reasons other than showing identical triplets to be very similar to each other. Do NOT abandon the film half-way through; that's when the big "plot twist" occurs!)
I think you are underestimating the influence of the environment.

Identical twins aren't identical. People who know them well can almost always tell them apart.
Identical twins are identical mostly in their looks. There's this set of twins I know long enough that a hypothetical offspring of a hypothetical union between me and one of them would be allowed to vote and drink alcohol, and I've been close friends with half of it for the better part of that time. I still sometimes struggle to tell them apart in photos. As soon as you meet them in real life, all doubt is gone. They have different goals in life, different hobbies, different mannerisms, different ways to talk, walk, move. And they've lived together for most of their lives.
It is more likely that identical twins will have different goals/hobbies etc if they live together than if they grew up separately. There is the urge to be individuals, and that desire will cause them to purposely find divergent interests. Those that are brought up separately don't have the factor of needing to be different, so they can quite often be more alike.
 
I thought studies on twins separated at birth and raised in different families showed identical twins can have similar interestsand characteristics.




To form identical twins, one fertilised egg (ovum) splits and develops two babies with exactly the same genetic information. This differs from fraternal twins, where two eggs (ova) are fertilised by two sperm and produce two genetically unique children, who are no more alike than individual siblings born at different times. Twins are more or less equally likely to be female or male. Contrary to popular belief, the incidence of twins doesn’t skip generations.

Fertilisation​

Hormones secreted by the ovaries, and a small gland in the brain called the pituitary, control the menstrual cycle. The average cycle is around 28 days. After a menstrual period, rising levels of the hormone oestrogen help to thicken the lining of the womb (the endometrium) and release an egg from one of the ovaries (ovulation).

If the egg is fertilised on its journey down the fallopian tube, it lodges in the thickened womb lining, starts dividing and evolves into an embryo.

Identical or ‘monozygotic’ twins​

Around one in three sets of twins is identical. This occurs because the fertilised egg divides in two while it is still a tiny collection of cells. The self-contained halves then develop into two babies, with exactly the same genetic information.

Twins conceived from one egg and one sperm are called identical or ‘monozygotic’ (one-cell) twins. The biological mechanisms that prompt the single fertilised egg to split in two remain a mystery.

Approximately one quarter of identical twins are mirror images of each other, which means the right side of one child matches the left side of their twin.

Fraternal or ‘dizygotic’ twins​

Around two in three sets of twins are fraternal. Two separate eggs (ova) are fertilised by two separate sperm, resulting in fraternal or ‘dizygotic’ (two-cell) twins. These babies will be no more alike than siblings born at separate times. The babies can be either the same sex or different sexes, with the odds roughly equal for each.
 
Did anyone hunt down and watch the Three Identical Strangers documentary? VERY interesting.

It does sound interesting - but alrming when I read that the “parents were chosen,” because it implies the entire lives of these three people was an unwilling experiement…

I'm really interested in this subject. can anyone here give me about ten book titles to start off reading?

@BH
I really love the book, “Endless Forms Most Beautiful” by Sean Carroll regarding evolutionary development (evo devo). It gives great information on this and is written for thouse outside of the field. I won’t say “lay people” because I think you need a certain amount of science or math study to really catch all that he is saying.

Also, Carroll did several videos for the Howard hughes Medical Institute (HHMI) on traits that you can look up on the interwebs.
 
Did anyone hunt down and watch the Three Identical Strangers documentary? VERY interesting.

It does sound interesting - but alrming when I read that the “parents were chosen,” because it implies the entire lives of these three people was an unwilling experiement…

Definitely. The first half of the documentary was a fun "feel good" story which I almost turned off — I already feel good! :cool:

But I kept going for a few minutes more and ... What The F**K!!!!
 
I'm really interested in this subject. can anyone here give me about ten book titles to start off reading?

@BH
I really love the book, “Endless Forms Most Beautiful” by Sean Carroll regarding evolutionary development (evo devo). It gives great information on this and is written for thouse outside of the field. I won’t say “lay people” because I think you need a certain amount of science or math study to really catch all that he is saying.

Also, Carroll did several videos for the Howard hughes Medical Institute (HHMI) on traits that you can look up on the interwebs.
Seconded. Note that it's by Sean B. Carroll, the biologist, not Sean M. Carroll, the much more famous physicist. Sean B. Carroll is the better writer by a country mile.
 
Did anyone hunt down and watch the Three Identical Strangers documentary? VERY interesting.

It does sound interesting - but alrming when I read that the “parents were chosen,” because it implies the entire lives of these three people was an unwilling experiement…

I'm really interested in this subject. can anyone here give me about ten book titles to start off reading?

@BH
I really love the book, “Endless Forms Most Beautiful” by Sean Carroll regarding evolutionary development (evo devo). It gives great information on this and is written for thouse outside of the field. I won’t say “lay people” because I think you need a certain amount of science or math study to really catch all that he is saying.

Also, Carroll did several videos for the Howard hughes Medical Institute (HHMI) on traits that you can look up on the interwebs.
The whole twin study by the Louise Wise adoption agency would be considered highly unethical these days. .. it was sketchy back then I think. What isn't mentioned is that some of the identical twins that were split were chosen because of mental health issues of the mother.
 
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