Today’s New Reason To Believe

Posted by Fazale ‘Fuz’ Rana, Ph.D.
[Originally posted on November 01, 2007]
Microbes and DNA from 8-Million-Year-Old Ice Shed Light on Origin-of-Life Question

We have a chest freezer in our garage that stores all the food that won’t fit in our kitchen refrigerator’s freezer. When it’s time to get something from the freezer, it usually comes from the top. It’s just too much work to dig down into the chest to get to a package of frozen food. Eventually stuff at the top finds its way down toward the bottom as food gets moved around and new items are added. On the rare occasion when somebody works up the motivation to “drill down” to the freezer’s bottom, they usually encounter barely recognizable items covered with a thick coating of frost or meat with severe freezer burn. Either way, nobody wants to eat the food from the bottom of the deep freezer. The good stuff is found at the top.

A team of scientists on a quest for “good stuff” recently drilled down into Earth’s deep freezer in the Mullins and Upper Beacon Valleys of Antarctica. And good stuff they found. The researchers recovered viable microbes and DNA from ice samples dated between 100,000 and 8 million years in age. It was like finding a popsicle in the bottom of the freezer.

This remarkable discovery bears important implications for the origin of life, calling into question the likelihood of life originating in comets or being delivered to Earth by these icy vehicles. Scientists are interested in looking for microbial life in the ancient ice sheets of Antarctica because such a discovery provides insight into the limits of biological activity and the preservation of life. It also provides a record of ancient life forms and a window to Earth’s past.

Scanning electron microscopy revealed the existence of filaments in the ice samples, which are taken as evidence for the presence of microorganisms. The researchers confirmed this interpretation by demonstrating metabolic activity in the ice through the uptake of radiolabeled amino acids and nucleotides and the breakdown of radiotagged glucose.

Based on these results, they successfully attempted to cultivate microbes from the ice. The researchers noted that the best stuff was found near the top of the Antarctic deep freezer. They were able to recover more microbes and a greater diversity of bugs in the younger ice samples.

The team also searched for community DNA in the ice. To undertake this endeavor they applied genomics techniques to enable direct sequencing of DNA isolated from the ice, without isolating and culturing the individual species of microbes.

They detected, based on DNA, 30 different types of microbes in the ice. The researchers noted diminished diversity in the older ice samples (as was the case for the metabolic studies and cultivation work).

They also characterized the fragment size of DNA in the ice and, once again, noted a greater degree of fragmentation and smaller fragments in the older ice samples. Using this data, the scientists estimated the half-life of the fragmentation process to be about 1.1 million years. The rate of breakdown indicates that cosmic radiation impinging on the ice is the primary driver of DNA fragmentation.

The relative instability of DNA in the ice and the loss in the viability of the microbes over the span of 8 million years makes it unlikely that life could arise in comets or be transported through interstellar space in these frozen bodies. Comets consist of frozen water along with dust and rock. The ice in Antarctica serves as a good model for the preservation of life and durability of biomolecules in comets. In fact, the ice in Antarctica represents the best-case scenario for survivability. Even though this region of Earth receives the highest dosage of cosmic radiation, it is not nearly as harsh an environment as interstellar space.

The short half-life of DNA and the limited viability of microbes after 8 million years in the ice of Antarctica makes it difficult to envision how life could emerge in comets of survive a journey of any length between star systems or within a solar system.

Now, to defrost my freezer. I hope I don’t find any originating life in the ice.

Posted by Fazale ‘Fuz’ Rana, Ph.D.

Lice DNA Supports Biblical Account of Humanity’s Creation

Every parent dreads receiving a note from their children’s school announcing an outbreak of lice. Messages of this sort set in motion a series of unpleasantries for the child, parent, and sometimes the rest of the family.

Some anthropologists, however, take a certain delight in lice infestations. These obligate surface parasites, and their genetic variability, offer insight into human origins and the migration of the first people around the world.

Most scientists who study lice are interested in these parasites for biomedical reasons. For example, some choose to focus on the natural history of these disease-causing organisms. Learning about the timing and location of lice origins, the historical pattern of their spread, and consequently, the contemporary distribution of their genetic variation helps biomedical researchers understand how infectious diseases harbored by insects spread. This information can potentially lead to more effective public health programs and, in some cases, treatments.

In the process of studying the origin and natural history of human parasites, like lice, molecular geneticists have stumbled upon an exciting new way to characterize humanity’s origin and movements around the world. Researchers believe that the timing and location of the origin, as well as the spread, of disease-causing and disease-harboring pests around the world mirrors the timing and location of the origin and spread of humanity. As such, the worldwide genetic variation of these infectious agents can be used in the same way that molecular anthropologists use human genetic variation to gain understanding of human prehistory.

A remarkable study on the global circulation of head lice illustrates how this creature can be used to track the spread of humanity around the world.*

There are three types of head lice (based on genetic fingerprints) distributed around the world: types A, B, and C. Type A is found throughout the world. Type B occurs in North and South America, and Europe. Type C is rare and geographically restricted to Ethiopia and Nepal.

Some investigations posit that Type A head lice established its association with modern humans in Africa shortly after the first people appeared. Type B originated in Europe after humanity spread into Asia and then Europe. Accordingly, Type B head lice appeared in the New World when Europeans colonized the Americas. If this model is correct, then Native Americans would have carried Type A head lice with them when they originally migrated into the Americas from Asia.

Researchers recognized a unique opportunity to test this model with the discovery of pre-Columbian mummies in Peru, dating to about 10,000 years in age, well before the Spanish and Portuguese arrived.

Anthropologists were able to recover the remains of ancient lice from the hair of the mummy. They then successfully extracted DNA from the lice specimens, then amplified and sequenced it. The lice possessed the Type A DNA fingerprint. This result means that the first immigrants into the Americas most likely carried the same genetic version of lice as the first humans in Africa. Type B lice must have been introduced by European settlers.

The natural history of lice matches the expected pattern of the Out-of-Africa hypothesis for human origins. Though often presented and discussed within the context of the evolutionary paradigm, this model has profound biblical implications. This hypothesis, which is substantiated by numerous studies, maintains that humanity originated recently (about 100,000 years ago) from East Africa (near the location theologians ascribed to the Garden of Eden) from a small population. Studies using mitochondrial and Y chromosomal DNA markers trace humanity’s origin back to a single man and woman. The genetic data also indicate that humanity’s migration around the world began at or near the Middle East.

If humanity’s genesis happened in the way described in Scripture, the genetic diversity patterns observed among international people groups would be very similar to those discovered by anthropologists. It looks as if Adam and Eve really existed, giving rise to all humanity.

For a detailed discussion of the myriad evidence in favor of the Out-of-Africa hypothesis and the use of parasites to characterize the origin of humanity see my book Who Was Adam?

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*This study made science news headlines when first published. I discussed the scientific and biblical implications of this research on the February 11, 2008 edition of our new podcast, RTB’s Science News Flash. This podcast offers a unique Christian perspective on headline-grabbing discoveries. A free subscription is available through iTunes.

Posted by Fazale ‘Fuz’ Rana, Ph.D.

Three New Studies Support Biblical Account of Humanity’s Creation

What’s the first thing that comes to mind when you think of the state of Kentucky? Horse racing? Wildcat basketball? The Louisville Slugger? Bluegrass music? What about burgoo?

Though most people probably haven’t heard about this spicy stew, it’s as much a part of the traditions of the Bluegrass State as the Kentucky Derby. Burgoo consists of a mixture of meats (beef, chicken, pork, mutton, and game animals, if available) and vegetables cooked (and re-cooked) in a large kettle over an open flame until all the flavors meld together. No two Burgoo recipes are the same. The preparation and consumption of Burgoo serves as a center piece for social gatherings. At times the entire community contributes the ingredients to make a large pot of stew.

Molecular anthropologists have recently concocted a burgoo of their own consisting of discoveries that turn the heat up on the support for the Out-of-Africa hypothesis of human origins, and with it, the biblical account of humanity’s beginnings.*

Out of Africa Hypothesis

In a nutshell, this model (also called the replacement model) maintains that modern humans evolved recently (about 100,000 years ago) in East Africa from a small hominid population and then migrated around the world to replace pre-existing hominids. Proponents believe that Homo neanderthalensis and Homo erectus are evolutionary side branches and dead ends.

Relative Proportion of Harmful Mutations in European and African Populations

One recent study, carried out by an international team, examined genetic variation in fifteen African American and twenty European Americans. These workers characterized genetic variability by examining single nucleotide polymorphisms (SNPs) and categorizing the DNA sequence differences as benign, possibly damaging, and probably damaging.

They noted that African Americans harbor a greater degree of SNP diversity than European Americans. Interestingly, European descendents have a greater proportion of harmful variations than people with an African ancestry.

These results find explanation if humanity arose in East Africa from a small population, and recently migrated into Europe through a genetic bottleneck. Bottlenecks result when a population drops to low levels and then recovers its numbers, or if a small subpopulation becomes separated from the main group and then later grows in size.

Genetic and Copy-Number Variation

Another study characterized the genetic variability of twenty-nine populations from around the world by monitoring 525,910 SNPs and 396 copy-number differences.

Again, the patterns of genetic variability noted in these two studies for people groups from around the world fit with the predictions of the Out-of-Africa hypothesis.

A third recently reported study focused on about 650,000 SNPs found in the genomes of 938 people representing 51 populations from around the world. The SNP data clustered into a number of groups displaying a geographical relationship that indicates an African origin of humanity and subsequent spread around the world.

Overwhelming Evidence for the Out-of-Africa Hypothesis

These three new research reports can be thrown into a large simmering kettle of studies that support the Out-of-Africa model. (For a detailed discussion of the myriad evidences in favor of the Out-of-Africa Hypothesis see the book Who Was Adam? Collectively, the consensus that emerges from this work indicates that humanity originated recently (about 100,000 years ago) from East Africa (near the location theologians ascribed to the Garden of Eden) from a small population. Amazingly, studies using mitochondrial and Y chromosomal DNA markers trace humanity’s origin back to a single man and woman. These studies also indicate that humanity’s migration around the world began at or near the Middle East.

Though often presented and discussed within the context of the evolutionary paradigm, this model has profound biblical implications. In some respects, the Out-of-Africa hypothesis appears to be the biblical model awkwardly forced into the evolutionary framework, like an incorrect puzzle piece. If humanity’s genesis happened in the way described in Scripture, the genetic diversity patterns observed among people groups around the world would be very similar to those discovered by anthropologists. It looks as if Adam and Eve really existed, giving rise to all humanity.

Next week I will describe another study using DNA extracted from ancient head lice that also lends credence to the biblical account of humanity’s origin. I decided it would be best not to describe this work for now. I didn’t want to ruin anybody’s appetite.

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*These studies made science news headlines when first published. I discussed the scientific and biblical implications of this research on the February 22, 2008 edition of our new podcast, RTB’s Science News Flash. This podcast offers a unique Christian perspective on headline-grabbing discoveries. A free subscription to this podcast is available through iTunes.