sullster

I have read this in the science sections of a few newspapers and a magazine. What do you students of genetics think of this? I would enjoy some clarification and explanation.

A 2% difference in the DNA of humans separates them from the Chimpanzee. There is a 2% difference between the DNA of human males and females. These 2% differences must be of a different kind. Is there a 2% genetic difference between males and females of other primates? I could keep asking lame questions but I prefer you genetics people to help me out here.

An inquiring mind wants to know.

MortalWombat

Hint: Females do not have a Y chromosome.

sullster

Understood. So why was this 2% story news? Was it just a bit of trivia or what?

Humans and chimps differ by 2%. I just want some clarification about this 2%. The difference between human males and females is not the same as the difference between humans and chimps.

Farren

Sullster what it comes down to is that the Y chromosome causes the development of male characteristics in males, and is responsible for the net 2% difference.

In other words the 2% difference in DNA is the coding that makes men male. While on the face of it the it may seem surprising that the same proportion of DNA code that differentiates men from women differentiates human from chimp - its not so surprising when you consider that at one point a human fetus is almost indistinguishable from a lizard fetus during its growth in the womb.

The reason is that DNA doesn't represent a "blueprint" for a human the way a building plan is a "blueprint" for the resulting building. Rather, its a chemical catalyst for a chain of reactions that ends up as an organism, similar to the tiny formula needed to generate a fractal graphic (like the mandelbrot set), or the formation of complex and elegantly symmetrical snow crystals from a chemically simple nucleus.

A side note. Apparently (one hears odd stories in Africa) there are instances of humans and certain other primates producing living offspring, although like mules (the offspring of horse and donkey matings) they were infertile.

Doubting Didymus

I think that's teriffically unlikely. We HAVE gotten human and ape gametes to fertilise in the lab, but the zygote didn't do anything.

Farren

DD, you may be right, the stories are anecdotal and not confirmed by reliable sources.

Arken

Unless my memory is faulty, I thought that the zygotes were terminated before they were given a chance to go through more than a few divisions.

villainess

I think that was an H. P. Lovecraft story, actually.

I guess I wouldn't be terrifically surprised if it turned out to be technically possible to get, say, a "humanzee" or a "chuman" but I wouldn't be surprised if it were impossible, either. The world may never know, or at least never admit to having found out.

I can't help being morbidly curious whether it would be more feasible to hide the offspring of such an experiment in the monkey house, or on a Greyhound bus in Indiana.

the.villainess

sullster

Thank you Farren for your reply,

I understand that the genes are not a "blueprint" for a fixed final end, but are really a recipe.

I still don't understand why this 2% story was put into newspapers and a magazine last month, if it is no big news. It would be like reporting some totally accepted fact like the structure of DNA in the science section as something new.

This may be a good idea for a thread. That is the nature of scientific "news" which is reported to the general public. I am a "general public" type. I am not schooled in science, but have an enormous curiosity about it. I absorb what science I can from science magazines and from books written for the public.

MortalWombat

Correct. In the case of the differences between males and females, The vast majority of the 2% difference is due to the presence or absence of the Y chromosome, while the difference between chimps and humans (ie male human vs male chimp or female human vs female chimp), is that the 2% is spread out over all the chromosomes. So on average, for every sequence of human DNA that is 100 nucleotides long, the corresponding sequence in chimps will be identical at 98 positions. Whereas if one compared the somatic (non sex determining) chromosomes of a human male and female, almost every 100 nucleotide sequence will be identical between the two.