Earlier this year, a DNA study suggested that human and chimp ancestors may have interbred to create hybrids. In the above article, biologist Eric Lander said that “The genome analysis revealed big surprises, with major implications for human evolution.”
This lead me to ponder why we are not hearing of more DNA studies of species assumed to be closely related. It would seem to me that studying the DNA would be superior to saying that some aquatic animal’s fin looks like a mammalian leg if you squint really hard.
All right, that’s an exaggeration, but still, isn’t it true that studying the DNA would give us more definitive answers than categorizing according to more subjective factors, such as body structure? After all, although evolution (through natural selection) acts mostly on the phenotype, it is the DNA that records the changes, however they occurred. Thus, evolution is more or less the process of altering the DNA code. To use an analogy, using the body structure to map evolution is like examining food to find the ingredients instead of simply looking at the recipe card. Yes, you can probably find out a bit by examining it, but you can know for sure by reading the information directly.
So if we do compare DNA as a method of mapping evolution, what would we come up with? Let’s look at a factor, say, chromosome number. How has the chromosome number changed over the course of evolution? How can a lobster have more than 100 pairs of chromosomes, a fruitfly have 4 pairs, and humans have 23?
It is looking at the DNA, in my opinion, that will make or break evolution. We need to get past the other arguments and get to the source, the DNA.
I am an eighteen-year-old college freshman at UC Berkeley who became interested in politics at a young age. Besides being part of the Berkeley College Republicans, Berkeley Students for Life, and KALX, I enjoy reading, singing, and playing guitar. One of my main interests is sharing my opinion at my personal blog and at the ACYU, of which I am a co-founder. Email me: 
July 29th, 2006 at 6:48 pm
“It would seem to me that studying the DNA would be superior to saying that some aquatic animal’s fin looks like a mammalian leg if you squint really hard.”
Katelyn, you had me laughing on the floor with that one! Great line!
July 29th, 2006 at 10:35 pm
Katelyn, the study of DNA as a molecular basis of genetics has required advances in biology, chemistry, physics, and computer science. Most of what we know has been discovered in the last 50 years. The mapping of the human genome did not start until the late 1980s. This might sound like a long time ago to you, but it is yesterday in terms of scientific advancement.
It is not surprising you don’t hear more when the “evolution debate” usually centers around statements based on theories from before the discovery of DNA. The squinting at aquatic fins is what the anti-evolution partisans do. Science has been busy studying DNA.
Your questions about what is possible to understand with DNA are all good and appropriate. DNA does give us a basis for understanding evolution and taxonomy. I encourage you to take some biology classes when you finally get to a university. In the meantime, start reading. A lot of information is out there. And a lot of questions are still the subject of research.
You specifically asked about chromosome number change. Here are some articles for you to read. Don’t expect to completely understand them — at least not unless you do some study.
http://www.talkorigins.org/origins/postmonth/jan99.html
http://www.talkorigins.org/faqs/faq-speciation.html
http://www.gate.net/~rwms/hum_ape_chrom.html
This last one talks about the evidence for the fusion of two chromosomes in the ancestor of humans and other great apes to create chromosome number 2 in humans. [N.B. All great apes except humans have 24 chromosomes. Humans have 23 chromosomes.]
Happy learning.
July 30th, 2006 at 10:41 pm
“It is not surprising you don’t hear more when the “evolution debate” usually centers around statements based on theories from before the discovery of DNA. The squinting at aquatic fins is what the anti-evolution partisans do. Science has been busy studying DNA.”
Amazing! Anti-evolution partisans have infiltrated my public school. Surely, it is thanks to them that our textbooks never mention the DNA evidence for evolution. Yet, lucky for you, I have put my apparently miniscule biology knowledge to work to find what my textbook (dated 2002) actually says about the evidence for evolution.
The only things mentioned under evidence for evolution are: the fossil record, the geographical distribution of living species, homologous structures of living organisms, and similarities in early development. Granted, all of these are being explained in depth in the section where Darwin presents his evidence (i.e. They were all arguments before the 1950’s, as you so keenly noted), but they are all mentioned in present tense wording. For example, in the section titled “Homologous Body Structures”: “Further evidence of evolution can be found in living animals… Homologous structures provide strong evidence that all four-limbed animals with backbones have descended, with modifications, from common ancestors.” (It seems those anti-evolutionists have struck again!)
Anyways, if science has indeed been studying DNA, they have very little to show for it in terms of evidence for evolution. Instead of using almost meaningless terms like “species”, we should be defining things by percentage of genetic difference, or something similar. If this is already being done, then all the better. It is about time, considering how much other science has improved (cell phones, computers, etc.). But the question is, then, why are our arguments about evolution still in the 19th century, when our science is in the 21st?
July 31st, 2006 at 3:33 pm
Katelyn, I was a zoology major at one time and concentrated my studies on biochemistry and genetics, before I switched to computer engineering. Granted this was back before you were born, but still a lot was known and a lot has since been discovered.
Your textbook, as you note, is presenting Darwin’s theory. Darwin’s observations are evidence for evolution. Darwin didn’t know about the physical mechanisms for inheritance, i.e. DNA.
When/if you get to Stanford, take the following course:
BIOSCI 113/244. Fundamentals of Molecular Evolution—(Graduate students register for 244.) The inference of key molecular evolutionary processes from DNA and protein sequences. Topics include random genetic drift, coalescent models, effects and tests of natural selection, combined effects of linkage and natural selection, codon bias and genome evolution. Prerequisites: Biological Sciences core or graduate standing in any department, and consent of instructor.
July 31st, 2006 at 3:50 pm
You ask: why our arguments are in the 19th century instead of the 21st century?
To understand evolution, genetics, and the physical mechanism for genetics requires a college-level study of the sciences. You should be able to grasp onto the main facts with 2 years of college-level biology and chemistry. Most people do not have that level of education — including the clerics who make pronouncements concerning evolution.
As you have noted in the past, standards for high school graduation are awfully low. Don’t be satisfied with your geared-to-the-mean high school understanding of biology. Go to college and learn with an open mind. If you are a smart girl, you’ll find a lot of what you’ve been told comes from people passing along ignorance in the guise of truth and wisdom.
August 1st, 2006 at 7:55 pm
As much as I enjoy hearing about your intellectual superiority, I would much rather have your opinion about the subject of the post. Here are some questions to keep you on track, if you wish to continue in this discussion:
Why doesn’t my biology textbook include DNA as evidence for evolution? Why is the only evidence listed from Darwin’s time? Is this because no new developments have occurred? Is it because developments have occurred, but the scientific community has been too busy to change their argument? Is it because the new developments are inferior to the old ones, and aren’t worth publishing? Is it because students studying biology can’t be expected to understand the new thinking behind evolution, but should just accept it? Could it be that the writers of my book are “behind the times”, yet one has had over 70 research papers published in journals such as Scientific American, and another is working with NOVA on a feature entitled “The Evolution Project” ? If it is none of these, then what is it? Surely, for someone who has studied at the college level, these are simple questions.
August 1st, 2006 at 11:15 pm
Katelyn, don’t be impudent. My comment was not about intellectual superiority, but to establish that it does take some education to understand these subects.
First, Scientific American is not a journal. It is a popular science magazine. A publication in Scientific American has close to zero value in academia.
I can’t answer for the motivations of your textbook authors. I suspect it is a complex of reasons, not the least of which is political. No, that doesn’t mean your textbook author is biased. It means he sells his books into a politically charged environment.
Now, instead of taking this discussion off track, did you read the links I gave you? Did you understand them? Do you have questions? If you had read them and understood them, I don’t think you’d be so confused about DNA as a basis for evolution.
August 2nd, 2006 at 6:44 am
I’m going on vacation until Saturday, so I will respond then.
September 5th, 2006 at 9:48 pm
“All great apes except humans have 24 chromosomes. Humans have 23 chromosomes.”
You say it that way, but your last article states it as humans and great apes. I have never heard of us being referred to as great apes. I have heard of us having a missing link ancestor with a great apes. I have heard that all the missing links thus far have been proven as hoaxes or mistakes back in college. Even if there has been a common ancestor we have diverged enough that we don’t fit into that category with them.
“Most people do not have that level of education — including the clerics who make pronouncements concerning evolution.”
I am sorry to inform you that Vatican scientists have PHDs and this lack of ignorance has not brought them to your side. So I don’t buy it. Then again I am in a mood tonight. Truth is truth. I can know truth thank you very much and ‘night.
September 7th, 2006 at 2:29 am
Chrysd, please see the following wikipedia article.
http://en.wikipedia.org/wiki/Ape
I’m not naive and think wikipedia is the definitive source. I cite it only to verify that I am not the only one who believes humans are properly classified with the great apes. Do a little digging and you’ll see it is a matter of debate/disagreement in the scientific community.
For me, it kind of comes down to whether you decide that Humans and the other Great Apes are in separate families. Most modern classifications put both humans and other Great Apes into the same family, Hominidae. 18th century taxonomic classifications put humans in Hominidae and other great apes into Pongidae. Some classifications try to fudge a little and put both into Hominidae, but then create separate “sub-families”.
As for the Vatican scientists having PhDs, that is a good thing. But, don’t go thinking they will disagree until you ask them. I think you are assuming a bit much if you think they do not believe in evolution. You might be surprised what vatican scientists believe. While you are over at wikipedia checking out Apes, you might also want to look at this article:
http://en.wikipedia.org/wiki/Georges_Lemaître
September 8th, 2006 at 1:43 pm
Hey! November 21 is going to be the unofficial day for national peace! Do something nice for someone else, pay someone else a compliment, tell a friend how you feel about them. Stop the hatred.
http://clothedinsackcloth.blogspot.com/2006/09/so-here-i-go.html
Repost this with the title Unofficial National Peace Day!!!
September 9th, 2006 at 9:19 pm
“This lead me to ponder why we are not hearing of more DNA studies of species assumed to be closely related. It would seem to me that studying the DNA would be superior to saying that some aquatic animal’s fin looks like a mammalian leg if you squint really hard.”
How odd that you would ignore all the DNA studies that have been done and are being done. Treat yourself to a subscription of SCIENCE magazine and you’ll get all the latest peer-reviewed research on a weekly basis.
By the way, “squinting hard” isn’t what anatomists do.
September 10th, 2006 at 8:39 am
hi!
thanks for your questions. i totally agree with you. i guess i didnt articulate it well enough. when i say the church should be a place for refuge i am saying that people, such as homosexuals, shouldn’t be kicked out just for the fact that they are homosexual. there is a difference between helping with the sin, and helping the person commit the sin. by inviting people who the church deems “sin more” than others (which i also believe isnt biblical) into the church they aren’t helping them sin, or saying its okay. but by treating them the same as everyone else, while recognizing there own sins is what i was saying should be happening. i mean thats the starting point in my mind. so- after they started attending regularly, may be they would make close relationships with people, and be more willing to hear what God has to say about however they are sinning. i dont think that people such as child molesters, rapist, murderers, homosexuals, drug dealers or anyone should be kept out of the church just beause they aren’t living the way God asks them to. i dont believe the church is JUST for the people who belong to it, but also for those who DONT belong to it. Like i think that Jesus would have eaten with those people, and possibly not with the ones who consider themself “holy” and “without sin.” does that make more sense?
and with the thing about the “blowhorn guy” who assumed i wasnt a christian because i was going to a punk rock concert, i agree, but it happend. when he walks around boston, it at least comes across that he since he doesnt know who is a christian and whos not, that he approaches it like everyones a non-christian. i mean he is a really nice guy, but becase i decided to go to a fall out boy concert (this was way back before people knew who they were) and there were kids with piercings between their vocal chords and stuff, that we were all automatically non christians and in need of Jesus, and it wasnt just my perception, i was with some friends who felt the same way.
but yea. thanks for liking my idea. i kind of want to get it out there, and really make it a day, but unfortunately i dont feel like i have as much power to do that, as i would like.
i am just really tired of hearing people hating eachother all the time. i don’t think that is what God had in mind, ya know?
have a great day!
becca
September 12th, 2006 at 10:10 pm
Maezeppa:
Normally, people do not go about ignoring things by deliberately mentioning them in the first sentence, as I did: “Earlier this year, a DNA study suggested…”. My point was wondering why we are not hearing more about DNA studies and how new technology supports evolution. For instance, as I mentioned earlier, my textbook only mentions evidence for evolution from Darwin’s time, and does not mention DNA support. Incidentally, my textbook author contributes to Science.
By the way, “squinting hard” is hyperbole.
September 12th, 2006 at 10:34 pm
Yeah, I get what you’re saying Becca. Just another thought:
I think another factor in deciding who “should” be in church is how they respond to criticism. When someone refuses to acknowledge that they are doing anything wrong, I think there’s a problem. I’m not talking about when someone tries hard, but ends up sinning, because we all do that. To use the alcoholism analogy again, the first step of Alcoholics Anon. is to admit and recognize the problem. I think that’s the first step to recovery from sin too. If someone can’t recognize their problem, it is hard for them to fix it.
If someone isn’t trying to stop sinning at all, this creates a problem for the rest of the community. It’s like a member of AA drinking margaritas at the meeting. It can hurt the other people in their own struggle, because unlike Jesus, we can sin, and will.
I think it’s kind of a fine line with people who refuse to recognize their sin. On one hand, the community would want to help them by having them near, but on the other hand, their behavior can damage other people’s struggles against sin.
So anyways, that was my (long) thought. What do you think?
September 14th, 2006 at 6:17 pm
That does seem rather odd that your textbook would completely neglect to include any information on DNA research. However, it does seem clear that DNA research into evolution has been conducted for quite some time, and this recent study simply recieved more public attention. For example, a search of the National Geographic news site, the same source you linked to above, returns around 160 results for “evolution dna,” many of which appear to relate to DNA studies with relevance to evolution.
Chrysd, PBS has a nice timeline outlining the evolution debate at http://www.pbs.org/wgbh/evolution/religion/revolution/1990.html . One important event mentioned is that in 1996, Pope John Paul II stated that “there is no essential conflict between evolutionary science and the world’s largest Christian faith.” It is very unfortunate, in my opinion, that Pope Benedict XVI doesn’t take that position as well.
September 21st, 2006 at 8:50 pm
I think there are many, many people who believe that Micro Evolution is full of facts that probably have correct conclusions, while Macro Evolution is full of Conclusions based upon some facts, but that the Conclusions are wrong or could be wrong.
Facts are always true by definition, but Conclusions and opinions may or may not be true.
The missing links in the Macro Evolution *theory* make the conclusions questionable at best.
That the street is wet is a fact. Drawing a conclusion that it therefore must have rained, is not.
Perhaps the street cleaner just sprayed the street.
That there are fossils of different species is factual.
The fact that some or all are similar can only be speculated upon. It may show that Macro Evolution is an opinion/theory or full of conclusions that may or may not be true.
Ever hear the old saying “Why reinvent the wheel?”
Why should God not use similar body parts when making different species? That doesn’t mean they came from the same origin, only that they are similar.
The same with God Changing DNA. Just because our DNA is similar to another species, does not necessarily “force” the conclusion that therefore we must be related. It may be one of the conclusions we could draw, but conclusions can be varied and are still conclusions.
Facts are true. Conclusions, opinions/theories may or may not be.
FAR.