Our 9th annual Darwin Day speaker was Dr. Alan R. Rogers, professor of Biology and Anthropology at the University of Utah. He addressed us on “The Genetic Admixture between Archaic and Modern Humans”
With our increasing ease of examining gene structure, we are starting to realize how very closely we are related to other hominids. For about six years we have known without question that archaic hominids and Neanderthals share genes with us.
Dr. Rogers described the nature of the evidence that supports this view. To start the investigation, comparing DNA from bones and teeth of ancient hominids with DNA from modern humans allows us to estimate the genetic mixing (admixture) using shared alleles (any of several forms of a gene which are found at the same place on a chromosome).
DNA of modern Eurasians and Neanderthals appears to be 1.5-2.1% identical. This same percentage holds true for modern people of East Asia and Papua New Guinea, but not Africa. Thus, gene mixing must have occurred after modern hominids left Africa but before they expanded throughout the world.
The technique of examining nucleotide site patterns allows us to differentiate between derived and ancestral alleles. The derived alleles are new and shared with Europeans and Africans. There are about 100,000 of these. The ancestral alleles are shared with ancients (notably Neanderthals and chimps). There are about 300,000 of these.
Matching derived and ancestral alleles to a population tree allows us to trace genes back in time to see where common ancestors diverged and where the mutations occurred that caused those separations and thus, the diverging populations.
In a cave in the Altai Mountains of Siberia which has been occupied on and off for 125,000 years, varying types of hominid DNA has been found. The cave is named Denisovan after the last occupant, Denis, a hermit in the 1700’s. A finger bone from this cave of a Denisovan woman called “X-woman” shows derived alleles most common in Australia, New Guinea and Oceania.
A derived allele (mutation) associated with lung physiology that allows Tibetans to live successfully at high altitude (and thus carry Sir Edmund Hillary to the top of Everest without using oxygen) is clearly from the Denisovan genome.
We have inherited our innate immune system from the Denisovans. It is old and used to defend against things we have had to fight for hundreds of thousands of years. (T-killer cell systems).
Further work delineating how much DNA modern humans share with Neanderthals is done with exclusively modern DNA. The longer a gene locus exists; the more time it has had for recombination mutations to occur. As generations pass, Neanderthal DNA gets broken up and recombined with non-Neanderthal DNA. The farther back in time a Neanderthal gene was present in our DNA, the shorter the Neanderthal nucleotide segment will be when examined. The research with modern genes focuses on long segments of chromosomes assessing the nucleotide recombinations.
But some Neanderthal DNA didn’t help them to survive and so was lost. Then, selection of beneficial genes became less effective because the population size was small. There weren’t enough Neanderthals to be able to shed the deleterious gene mutations and keep the benign or positive mutations. The health of a population depends upon getting rid of deleterious mutations. Neanderthals were on their way out when Homo sapiens arrived 20,000 years ago. We didn’t eradicate them.
However, many of the deleterious genes we inherited from them are still present in our population today. A predisposition for depression may be from Neanderthals, as is the propensity for obesity, Type 2 Diabetes, some skin textures, and certain kinds of heart disease.
This is not to say that new mutations are not occurring today. Solar rays, gamma rays, chemicals and other environmental effects break DNA. New non-infectious diseases are occurring, which shows that new mutations are currently arising. Cystic fibrosis is caused by a change somewhere in an enormous gene leading to thicker pulmonary secretions.
In the ensuing discussion all sorts of questions were entertained such as: How does one explain left handedness, which seems to have no evolutionary advantage? Dr. Rogers suggested that left handedness persists because the rare left handed person has the advantage of novelty in not being like all the other combatants. The “gene” for left-handedness creates a successful defense and thus persists.
Dr. Rogers fielded all questions sympathetically and with expertise; well-spoken and brilliant is our judgement. We thank him for his time and hope to hear from him again.
Dr. Rogers’ new book, The Evidence for Evolution (University of Chicago Press, 2011), demolishes the ideas of Creationists by using evidence and logic, rather than emotionalism and rhetoric. It is a perfect way to celebrate Charles Darwin.
—Lauren Florence, MD
Ideology and Theology
One of the biggest changes in politics in my lifetime is that the delusional is no longer marginal; it has come in from the fringe, to sit in the seat of power in the Oval Office and in Congress. For the first time in our history, ideology and theology hold a monopoly of power in Washington. Theology asserts propositions that cannot be proven true; ideologues hold stoutly to a world view despite being contradicted by what is generally accepted as reality. When ideology and theology couple, their offspring are not always bad but they are always blind. And there is the danger: voters and politicians alike, oblivious of the facts.
In conjunction with our 10th Annual Darwin Day Celebration in February 2017, Humanists of Utah will be staging a field trip to the Cleveland Lloyd Dinosaur Quarry on Saturday September 17, 2016. This is intended to foster interest in our February Celebration. Utah State Paleontologist Dr. James Kirkland will escort us on our approximately 8-9 hour bus trip 30 miles south of Price, Utah and back. If there is enough interest will may stop at the CEU Museum in Price, as well. Along the way Dr. Kirkland will tell us about the fantastic array of world class fossil beds that exist in Utah. He will also share some notes on the annual meeting of the Society of Paleontologists being held in the Grand Hotel in Salt Lake City this year. We have tentatively set the cost at $30.00 per person although there will be scholarships available. Lunch/snack options are still being discussed, we will also have suggestions on what to wear. This is a full size bus, not a van and will carry 50 persons.
Questions or RSVP contact Bob Mayhew at (801) 582-3160 or firstname.lastname@example.org.
On Sunday, February 28th from 1:30 – 3:00 in the afternoon, eight happy humanists gathered at Mestizo Coffeehouse in downtown Salt Lake City to discuss Humanist Ethics. It was a lively and engaging discussion, and we hope these monthly Sunday afternoon gatherings will continue to draw a diverse crowd from around the valley to discuss topics related to humanism and humanist philosophy for years to come!
To offer a recap for those unable to attend, Minister Elaine Stehel wrote down the many great answers participants gave to the following question: “What sources give you inspiration as you strive to make ethical decisions and lead an ethical life as a humanist?”
Science; computers; intelligence; love; respect; microscope set; curiosity; geomorphology; awe; wonder; earth; the universe; mystery; a goal to minimize harm; awareness of the consequences of our actions; guilt; a desire to do good to others and to see good in the world; the golden rule; honesty; and integrity.
Thank you to all those who were able to attend and we hope to see many more of you on the fourth Sunday of March, the 27th! If you would be more likely to attend if we held the discussions at a different coffee shop each month, please let Elaine know which locations would be most convenient to you and your family.
Happy March everyone! It is a little early to get too excited about spring, but it’s hard not to when it is so pleasant outside. However, even though it is pleasant out, it is not really “good weather,” because what we really need is much more moisture. But whether winter returns or not, I will be planting peas and other hardy crops soon. Also in that light I will continue to advocate for growing local and buying local where possible and for us meat eaters, we should buy local that is grass fed and treated humanely. I am finding this easier to do at the various weekend markets around the valley.
Anyway, in this month’s report, I have just a little rambling to do, as there are several items I want to touch on.
First I want to thank everyone who came to our Darwin Day celebration, I had a good time and I hope you did also. I also want to thank all those who helped make it happen, Art King for arranging for our speaker, Bob Mayhew for set up and take down, my nephew Chris Lane for set up and take down and Elaine Stehel for handling the merchandise and literature and helping promote the event.
As Elaine and I have been mentioning we are starting to plan the Tenth Annual Darwin Day with Humanists of Utah already. Our Darwin Day events have been smaller in size the last few years and we mean to change that by starting early and planning big. We are planning to have it at the University of Utah again as we did for the first several events. We plan to spread it out a little, with an afternoon and evening of things to do (as we did the first few years). This will all be possible if we get enough volunteers.
While I am mentioning volunteers I need to emphasize that having enough volunteers will determine how many other projects we can sponsor. We will have a kiosk at the Pride festival again this year and I will be there for that, but I will need help. There are also some street fairs in the summer that would be a good way to make ourselves Humanists of Utah) better known to the public. But in the last few years we had no volunteers, so no street fairs. I hope we can change that.
As I ramble I almost forgot that we had our first discussion group in quite a while. It was enjoyable to sit and talk again. Our old discussion group use to be one of my favorite things to do and I am glad it is back. This has been a project that Elaine has undertaken and I thank her for reviving it.
One more thing, you will see an announcement in the newsletter about our planned bus trip to the Cleveland-Lloyd Quarry in September. Amy and I have already RSVP’d and the chapter has reserved the bus so I hope you will RSVP and come along.
Finally, I will not be able to attend March’s meeting, as I will be heading to St. George for a memorial service on that day. But Elaine will pick up some of my cookies, so enjoy and I will see you soon.