Originally Posted by cheerfulgreek (Post 1660029)

One of the questions I asked her was "If the DNA sequence in humans is so close to that of chimpanzees, why do the two species look so different?"

Originally Posted by DSTCHAOS (Post 1661151)

;)

You said you knew she was inaccurate and didn't know. You had basic questions that you knew were probably challenging her limited knowledge-base. When people do that they have to understand that there's a thin line between challenging discourse and being an asshole show-off.

What better way to put a dunce cap on her and put yourself at the forefront as the leading authority during a ZOO TOUR. :)

Originally Posted by BigRedBeta (Post 1661179)

Was it really necessary for you to ask the presenter the same question a second and third time?

It's called being tactful.

Originally Posted by BigRedBeta (Post 1661176)

It's not that the mother's body rejects it, it's that the having either extra information (an extra chromosome hanging out) or missing information (having only one chromosome when you should have two) results in a non-viable fetus. This would be due to having too much or too little of needed protein or some other form of imbalance that affects the growth and development.

I base this off the fact that, in humans, there are no known viable complete autosomal monosomies (Cri du Chat syndrome is a partial monosomy of chromosome 5) and only the three previously mentioned trisomies. Just because we never see individuals with monosomies or trisomies other than the ones mentioned absolutely does not mean they don't occur, but rather, that they are completely non-compatible with even advanced intra-uterine age, let alone extra-uterine viability.

Further, in humans, more than 80% of all conceptions never make it to term, and roughly 50% of all conceptions have some sort of chromosomal anomaly that makes the pregnancy non-viable. It doesn't even necessarily have to be gross chromosomal abnormalities, as significant micro-deletions of chromosomes in the right places can create a non-viable pregnancy. Most often the pregnancy is spontaneously aborted within the first 4-6 weeks and so the woman doesn't even realize she's pregnant. (Not to open a can of worms, but these facts are one of my biggest arguments against the "life begins at conception" crowd).

Originally Posted by SOPi_Jawbreaker (Post 1661469)

A 2% difference in DNA may not sound like a lot but it is. I think there is a large amount of shared DNA across many different Eukaryotes, because a large number of our genes are just coding for the basics that we share (e.g. mitochondria, endoplasmic reticulum, Golgi apparatus, nucleus, ribosomes, cell membrane, centrioles, lysozymes, proteins, enzymes, ion channels, metabolic pathways, chemical pathways, replication, transcription, translation, cytokinesis, etc). We share about half our DNA with bananas and cabbages. That sounds like a lot of shared DNA, yet we look nothing like bananas or cabbages. If a 50% is that significant to produce such a difference between humans and fruits/vegetables, then think about how big a difference a 2% is still going to make.

Originally Posted by cheerfulgreek (Post 1661761)

Yes, this is true, but this is why I asked the tour guide lady about the small changes in regions of the DNA that have a customary or regular function in the appearance of the organism. That's why I also asked her if it could be a different developmental trajectory between chimps and humans. I mentioned that in an earlier post too.

Originally Posted by DaemonSeid (Post 1660230)

So what came first?

The chicken or the egg?

Originally Posted by DeltAlum (Post 1662030)

Some rooster.

Originally Posted by BigRedBeta (Post 1661176)

It's not that the mother's body rejects it, it's that the having either extra information (an extra chromosome hanging out) or missing information (having only one chromosome when you should have two) results in a non-viable fetus. This would be due to having too much or too little of needed protein or some other form of imbalance that affects the growth and development.

I base this off the fact that, in humans, there are no known viable complete autosomal monosomies (Cri du Chat syndrome is a partial monosomy of chromosome 5) and only the three previously mentioned trisomies. Just because we never see individuals with monosomies or trisomies other than the ones mentioned absolutely does not mean they don't occur, but rather, that they are completely non-compatible with even advanced intra-uterine age, let alone extra-uterine viability.

Further, in humans, more than 80% of all conceptions never make it to term, and roughly 50% of all conceptions have some sort of chromosomal anomaly that makes the pregnancy non-viable. It doesn't even necessarily have to be gross chromosomal abnormalities, as significant micro-deletions of chromosomes in the right places can create a non-viable pregnancy. Most often the pregnancy is spontaneously aborted within the first 4-6 weeks and so the woman doesn't even realize she's pregnant. (Not to open a can of worms, but these facts are one of my biggest arguments against the "life begins at conception" crowd).

Originally Posted by cheerfulgreek (Post 1661761)

Yes, this is true, but this is why I asked the tour guide lady about the small changes in regions of the DNA that have a customary or regular function in the appearance of the organism. That's why I also asked her if it could be a different developmental trajectory between chimps and humans. I mentioned that in an earlier post too.

Originally Posted by AKA_Monet (Post 1662046)

So what are the physicians calling the Turner's Syndrome and the Philadelphia chromosome in Fragile X these days?

Just asking because I haven't kept up with that research. :rolleyes:

Originally Posted by cheerfulgreek (Post 1660029)

...I told her I didn't know, but the only thing I could think of was that the small changes in regions of the DNA that have a regulatory function probably can have major effects on the appearance, I guess. I told her that maybe chimps and humans have different developmental trajectories...

Originally Posted by cheerfulgreek (Post 1661146)

...I thought my questions were pretty basic.

Originally Posted by AKA_Monet (Post 1662046)

Cheerful

The fertilized eggs are hypermethylated and the heterochromatin is wacky causing inappropriate crossovers and non-homologous end joining in the chromosomes.

Remember human eggs are EXTREMELY fragile unlike say mouse. Knockout/trangenics are rather difficult to do even with similar non-human primate species. And OLAW rules will NOT allow researchers to use chimps for molecular studies. The highest we researchers can get these days are baboons. But since NIH eliminated our budgets, doubtful anyone can pay for it... Even med and vet schools are are having difficulties with the animals they use for teaching...