January 11, 2017
Imagine, as a researcher, being able to travel through time – to have specimens and materials from the past but with the knowledge and technology of today.
While time travel remains a plot line for science fiction, research with past entities and materials is very much a part of science today. Instead of going back decades, researchers are using decades-old specimens – tissue, hair, fecal matter and even DNA – to answer critical questions about the natural world, how it’s changed through time and what effect humans are having on the species around them.
Such research is possible through collections like the Natural Science Research Laboratory (NSRL), part of the Museum of Texas Tech University that houses more than 5 million animal specimens from throughout the world, collected over decades, that likely will last another century or more, reaching ahead to even more generations of scientists.
“What’s neat is that 1,000 years from now there will be a biological record of what planet Earth looked like in 2016,” said Robert Bradley, associate chairman of the Department of Biological Sciences and director of the NSRL. “The material will be there for those guys 1,000 years from now to do whatever kind of research they’re doing. They can do their walk back through time.”
Although many universities have a collection of animal specimens on which to conduct research, Texas Tech’s collection is unusual in both its size and scope. Inside the building are millions of bones, tissue samples, genetic samples and preserved, full-sized animals that, to the trained researcher, catalogs the evolution of a species and a landscape over time.
This collection is a valuable resource for Texas Tech professors, but scientists throughout the world can access the collections as well.
“Having something this large at a university is very uncommon,” Bradley said. “It exists because of the research that faculty members do.”
The NSRL consists of five collections:
This collection has about 125,000 specimens from throughout the world, with a greater emphasis on the southwest United States and Central and South America, because more Texas Tech researchers have done research in those regions and brought specimens back with them. This is one of the largest mammal collections in the country and includes bats, rodents, coyotes and others, in addition to a number of game animals hunters have donated through the years. Those are used for education, not research.
The NSRL is home to about 4.5 million specimens of invertebrates. The collection is primarily insects and arachnids.
The bird collection has between 6,000 and 8,000 specimens, including skin, skeletal material, preserved bodies, nests and eggs. Those specimens are mostly regional, coming from Texas, Mexico and Central America but include members from every extant avian order.
About 350,000 tissue samples from 90,000 individuals make up this collection, which is shifting to new cryogenic storage in the next two years. The NSRL recently purchased liquid nitrogen tanks for the GRC, which will provide a temperature sufficiently low to ensure the samples are preserved for scientific research for centuries more.
Former director Robert Baker and Department of Biological Sciences professor Ron Chesser were among the first scientists to go into Chernobyl, Ukraine, after the nuclear disaster in 1986. They brought back rodents that were in the radiation zone and comparable species from outside the radiation zone. This collection allows researchers to study how radiation leads to genomic mutations. No other scientists archived any specimens, so no other collection in the world includes something similar.
These collections, which are becoming increasingly valuable as fewer universities invest in them, serve two major research purposes, Bradley said. First, they allow scientists to do comparative research. A researcher today can go to a certain region to see what species live in that region, what they eat, how they act and what their genes look like, then go to the NSRL and look at specimens (including DNA) from that region three or four decades ago. Thus, the researcher can tell how biodiversity among species in a region has changed over time and how a species adapts to the environment.
Second, having specimens from a project allow that project to be duplicated and fact-checked. Other scientists may disagree with a premise of the first study or with the conclusion drawn; having the same specimens available for a second look allows the study to be replicated and makes for better findings.
For scientists who want to answer the questions of the world, it also opens up 5 million possible questions.
“There is great biodiversity in the world, and if you have the right technologies and you’re clever enough, you can pick those groups to study and they can inform whatever you may be interested in,” said Caleb Phillips, the curator of the Genetic Resources Collection.
To the average person, a mouse is a mouse is a mouse.
To Robert Bradley, a mouse may be an entirely new type of mouse, though it looks similar, and a third mouse, with enough genetic sequencing, also may prove to be a unique type, even though only a few decades ago the best scientists in the world thought all those mice were the same species.
Bradley studies the genetic sequencing of mammals, mostly mice. His research looks at how animals have evolved to become different species and the role environmental factors play in that evolution.
One such example is mice that range from California to Texas and south into Mexico and Central America. This mouse is adapted to high elevation pine oak forests and typically are observed at or above 7,000 feet above sea level. All of the mountain ranges in these thousands of square miles have a different species of mouse on it.
Bradley theorized the mice were all one species more than 100,000 years ago when the region was less dissimilar, but as climate and geology changed, mice were isolated in different mountain groups, so they evolved differently from each other. This process is known as speciation and, over time, they will evolve so the two species of rodent are as different from each other genetically as a coyote and a wolf.
“The question remains, how did they adapt to all these different isolated groups?” Bradley said. “Did they adapt individually each time? Was there a common pattern? What had they done that makes each of these genetically unique?”
Bradley’s research is dependent on DNA testing and the ability to examine genomes and find the differences, since to the naked or uninformed eye most mice look like every other mouse. Since DNA sequencing was developed in the 1980s the technology has moved rapidly, and Bradley has used that improved technology with the specimens preserved at the NSRL and other collections to track the evolutionary differences of rodent species to rodent species over time. It led to an unprecedented amount of precise and telling information about these animals.
“What that opened up was this material collected 100 years ago can now be used for DNA analyses,” he said. “That’s kind of revolutionized natural history collections. We’re able to use contemporary material that current researchers are collecting and archiving, and you can now go back in time and routinely get material from things collected 100 years ago. It gives us that back-in-time component that we didn’t have.”
It’s not just animal evolution either. In the 1990s, a Hantavirus outbreak in the American Southwest raised a question about this apparently new disease. Scientists at the NSRL, using rodent specimens preserved for decades, looked back in time and determined rodents from more than 10 years ago also carried this virus, so it wasn’t new, it just hadn’t come into contact with humans.
He and his predecessor at the NSRL, Robert Baker, studied the speciation process looking at bats and rodents. They and other biologists consistently drew the same conclusions: there are many more types of animals on Earth than previously thought. In mammals, the best-studied class on the planet, scientists have underestimated the number of species by about 40 percent. They recognize 5,300 species today, where 20 years ago that number was about 4,400.
For a biologist, that’s both intriguing and frightening. Discovering more biodiversity today implies the Earth is home to more species than scientists know. It also suggests more species have gone extinct before scientists had a chance to discover them and may continue to, as extinction remains a major concern for many species.
“We’re hitting the point now where we’re starting to lose biodiversity, and we may be losing species at a more rapid rate than we realize, because if we don’t know what’s out there, we won’t know it’s gone,” he said.
Humans tend to label things good or bad. In science, it’s more a matter of perspective.
Bacteria is one example. Gene mutations are another. Take “Jurassic Park.” Anyone who watched the dinosaurs-gone-awry movies knows gene mutations can lead to a murderous rampage – from a human perspective. From an evolutionary perspective, it’s a story of survival: a gene mutation allowed a species to continue where it previously couldn’t.
Biologist David Ray isn’t studying dinosaurs, but he’s studying a few of their survivors to see how animals evolve and how much of it is luck of the draw. Ray, who is a computational biologist at Texas Tech, researches animals that bite – rodents, bats, crocodilians, even some insects. He looks at their genomes and examines how each species has evolved over time and in different environments. His lab examines why certain genomes evolve in particular ways and how that affects the species.
Of the average mammal genome, about 2 percent of it actually codes the animal to act, look and think a certain way. The rest of it, to use Ray’s term, is “other stuff.” That stuff is pretty interesting, though. It plays a sizable role how the genome is structured and how it functions.
About half of the average genome is made up of transposable elements, which are sequences in genomes that can make copies of themselves or move around, thus shifting other elements throughout the genome. A transposable element can move a gene around the larger structure, thus changing what it tells the organism to do.
“That can have a huge impact in the way a genome is put together and the way a genome functions,” Ray said. “By changing the structure of the genome, you change the function of the genome, which changes possibly the organism’s external appearance or the ability of the organism to do something.”
These elements, found in the genomes of all living things, including humans, are essentially parasites and are always active in the genomes. However, that 98 percent of the genome that is not important coding material is a lot of space for transposable elements to land with little to no effect. It’s only in that 2 percent where it can cause a mutation in the gene. And when that does happen, it’s labeled “bad” pretty quickly.
For example, the strain of hemophilia that runs through European royal families was caused a transposable element inserting itself into a gene and disabling that gene, thus hampering the blood’s ability to clot.
However, Ray’s research shows many examples of mutation that are positive – at least for the species in question. Much of his work is in bats, particularly the vesper bat, a group of little brown bats he first researched in West Virginia that occur nearly worldwide across half a dozen unique climates. There are more species in this group of bat than any other group known to scientists. This group also has unusual activity among its transposable elements. Ray is asking whether those facts are connected and how genetic mutation may have affected this group.
“Our suspicion is that it’s actually helped more than it hurt,” Ray said. “In order to evolve you have to have variation. If everybody’s identical, if a virus comes along and affects one individual, it’ll affect all the individuals. But with all of this weird transposable element activity, it’s going to be extremely variable, with more opportunities to change, occupy a new habitat or take advantage of a new food source.”
Compare the vesper bats to the phyllostomid bats, another group of flying mammals that evolved during the same time period and from the same habitats. Yet phyllostomids have extremely variable morphology, eat different foods and look different from vesper bats. They also haven’t spread; evolution has confined this group to the New World tropics.
This research showed how the two types of bats evolved in different directions. The bat specimens at the NSRL allow Ray to travel back in time, from a research perspective, and see how the bats have evolved from their previous selves and why these species went in such different directions.
Although scientists throughout the world use the NSRL collections, Ray came to Texas Tech in large part to have greater access to that resource. Once he discovered the weird genetic activity among the vesper bats, he wanted answers he wasn’t going to get from smaller collections.
“It’s an invaluable resource,” he said. “Our research has been immensely helped by having access to those resources.”
The Natural Science Research Laboratory (NSRL) is a division of the Museum of Texas Tech University committed to the mission of building and preserving a library of our planet's natural heritage for education and research purposes. The NSRL has been recognized as a leader in the development and use of innovative methodologies for biological collections care and data management.
The College of Arts & Sciences at Texas Tech offers a wide variety of courses and programs in the arts, humanities, mathematics, social and behavioral sciences, natural sciences, and communications. The largest of the Colleges at Texas Tech, it offers 120 degree programs in 15 departments.
The college offers 41 bachelor's degree opportunities, 34 master's degrees and 14 doctoral degrees.
More than 8,500 undergraduate and 1,100 graduate students are enrolled in the college.
The Department of Biological Sciences in the College of Arts and Sciences at Texas Tech University hosts a variety of academic degree programs aimed toward the advancement of knowledge, learning, teaching and research of the natural world.
The Department hosts a variety of centers and programs focused on the life sciences which provide research opportunities including: