Category: Genes

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Happy Birthday, BioBeat

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This month, our blog that highlights NIGMS-funded research turns four years old! For each candle, we thought we’d illuminate an aspect of the blog to offer you, our reader, an insider’s view.

Who are we?

Over the years, the editorial team has included onsite science writers, office interns, staff scientists and guest authors from universities. Kathryn, who’s a regular contributor, writes entirely from her home office. Chris, who has a Ph.D. in neuroscience and now manages the blog, used to do research in a lab. Alisa has worked in NIGMS’ Bethesda-based office the longest: 22 years! She and I remember when we first launched Biomedical Beat as an e-newsletter in 2005. You can read more about each of the writers on the contributors page and if you know someone who’s considering a career in science communications, tell them to drop us a line.

How do we come up with the stories?

We get our story ideas from a range of sources. For instance, newspaper articles about an experimental pest control strategy in Florida and California prompted us to write about NIGMS-funded studies exploring the basic science of the technique. A beautiful visual from a grantee’s institution inspired a short post on tissue regeneration research. And an ongoing conversation with NIGMS scientific staff about the important role of research organisms in biological studies sparked the idea for a playful profile of one such science superstar.

A big change in our storytelling has been shifting the focus from a single finding to broader progress in a lab or field. So instead of reporting on a study just published in a scientific journal, we may write about the scientist’s career path or showcase a collection of recent findings in that particular field. These approaches help us demonstrate that scientific understanding usually progresses through the slow and steady work undertaken by many labs.

What are our favorite posts?

I polled the writers on posts they liked, and the list is really long! Here are the top picks.


Four Ways Inheritance Is More Complex Than Mendel Knew


The Endoplasmic Reticulum: Networking in the Cell


Interview With a Scientist: Janet Iwasa, Molecular Animator


From Basic Research to Bioelectric Medicine


An Insider’s Look at Life: Magnified, an Airport Exhibit of Stunning Microscopy Images

What are your favorite posts?

We regularly review data about the number of times a blog post has been viewed to identify the ones that interest readers the most. That information also helps guide our decisions about other topics to feature on the blog. The Cool Image posts are among the most popular! Below are some other chart-topping posts.


Our Complicated Relationship With Viruses


The Proteasome: The Cells Trash Processor in Action


Demystifying General Anesthetics


Meet Sarkis Mazmanian and the Bacteria That Keep Us Healthy


5 Reasons Biologists Love Math

We always like hearing from readers! If there’s a basic biomedical research topic you’d like us to write about, or if you have feedback on a story or the blog in general, please leave your suggestions in the comment field below.

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Flipping the Switch on Controlling Disease-Carrying Insects

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Illustration of some of the jobs that the ER performs in the cell.

This image shows a mosquito egg. Wolbachia bacteria, which infect many species of insects including mosquitos, move from one generation to the next inside insect eggs. Credit: Wikimedia Commons, Mogana Das Murtey and Patchamuthu Ramasamy, Universiti Sains, Malaysia.

Suppressing insects that spread disease is an essential public health effort, and scientists are testing a possible new tool to use in this challenging arena. They’re harnessing a microbe capable of controlling insects’ reproductive processes.

The microbes, called Wolbachia, live inside the cells of about two-thirds of insect species worldwide, and they can manipulate the host’s reproductive cells in ways that boost their own survival. Scientists think they can use Wolbachia’s methods to reduce populations of insects that spread disease among humans.

A Switch to Control Fertility

Wolbachia have evolved complex ways to control insect reproduction so as to infect increasing numbers of an insect species—such as those prolific disease-spreaders, mosquitos. One method Wolbachia uses is called cytoplasmic incompatibility, or CI. The end result of CI, basically, is that the sperm of infected male insects cause sterility in uninfected females.

Wolbachia that have infected male insects can insert proteins that produce a kind of infertility switch into the host’s sperm. When the sperm later fuses with an egg from an uninfected female, the switch is triggered and renders the egg sterile. If the female is already infected, her eggs will contain Wolbachia, which can turn off the switch and allow the egg to develop. This trick ensures that more Wolbachia-infected insects will survive and continue to reproduce, while uninfected ones will be less successful.

Already, some states Exit icon and countries Exit icon are releasing Wolbachia-infected male mosquitoes into wild mosquito populations that carry disease-causing viruses to test this strategy for insect control. Males carrying a Wolbachia strain that strongly induces infertility in uninfected females should reduce the numbers of mosquito eggs that mature, leading to fewer mosquitos. Continue reading “Flipping the Switch on Controlling Disease-Carrying Insects”

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Sea Urchin Regeneration May Help Us Understand Aging

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Sea urchin

The variegated sea urchin typically lives for about 4 years in the wild. The close-up view shows the sea urchin’s spines and tube feet that regrew after being removed 15 days earlier. Credit: Helena Reinardy (left) and Andrea Bodnar (right), Bermuda Institute of Ocean Sciences.

If you’ve ever been to the beach and walked around the rocks during low tide, you’ve probably seen a sea urchin. You may not have known that sea urchins found along the Pacific shore can live for more than 100 years. What’s even cooler is that, as they age, they don’t seem to lose their abilities to reproduce or regenerate damaged body parts. While different species of sea urchins have varying life expectancies, they all seem to share fountain-of-youth characteristics. For these and other reasons, scientists study sea urchins to investigate aging and other basic life processes. Continue reading “Sea Urchin Regeneration May Help Us Understand Aging”

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Six Things to Know About DNA and DNA Repair

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Deoxyribonucleic acid, better known as DNA, was first identified on a discarded surgical bandage almost 150 years ago. Increasingly sophisticated tools and techniques have allowed scientists to learn more about this chemical compound that includes all the instructions necessary for building a living organism. From among the dozens of fascinating things known about DNA, here are six items touching on the make up of DNA’s double helix, the vast amounts of DNA packed into every human’s cells, common DNA errors and a few ways DNA can repair itself.

1. DNA is in every living thing.

Nucleotide
DNA consists of two long, twisted chains made of nucleotides. Each nucleotide contains one base, one phosphate molecule and the sugar molecule deoxyribose. The bases in DNA nucleotides are adenine, cytosine, guanine and thymine. Credit: NIGMS.

The chemical instructions for building a person—and every other creature on Earth—are contained in DNA. DNA is shaped like a corkscrew-twisted ladder, called a double helix. The two ladder rails are referred to as backbones, made of alternating groups of sugar and phosphate. The ladder’s rungs are made from four different building blocks called bases, arranged in pairs: adenine (A) paired with thymine (T), and cytosine (C) paired with guanine (G). Humans have about 3 billion base pairs in each cell. The order of the base pairs determines the exact instructions encoded in that part of the DNA molecule. Also, the sequence of DNA base pairs in one person is about 99.9 percent identical to that of everyone else.

2. Humans have a lot of DNA.

Humans begin as a single fertilized cell containing (with some rare exceptions) the full complement of DNA—the genome—arranged into 46 discrete chromosomes (23 pairs, with mom and dad each contributing half of each pair) in the cell’s nucleus. There are 6 feet of DNA coiled up tightly in that first cell. All the information in the DNA is replicated each time the cell divides. The amount of DNA packed into all of an adult’s cells is on the order of 100 trillion feet (about 19 billion miles)—so that if the DNA chain was stretched out, it would be long enough to reach back and forth between the Earth and the Sun more than 200 times. Continue reading “Six Things to Know About DNA and DNA Repair”

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Birthdays, Nobel Prizes and Basic Research

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James D. Watson
James D. Watson. Credit: Wikimedia Commons, Cold Spring Harbor Laboratory.

April 6 is the birthday of two Nobel Prize winners in physiology or medicine—James Watson and Edmond H. Fischer. They have also both been NIGMS-supported researchers.

Double helix model
In 1953, Watson and Crick created their historic model of the shape of DNA: the double helix. Credit: Cold Spring Harbor Laboratory archives.

James D. Watson, born on this day in 1928, was honored with the Nobel Prize in 1962. He shared it with Francis H. Compton Crick and Maurice Wilkins “for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material.” This laid the groundwork for future discoveries. In the early 1950s, Wilkins and another scientist, Rosalind Franklin, worked to determine DNA’s structure. In 1953, Watson and Crick discovered its shape as a double helix. This twisted ladder structure enabled other researchers to unlock the secret of how genetic information is stored, transferred and copied. Franklin is widely recognized as having played a significant role in revealing the physical structure of DNA; due to her death at age 37 in 1958, Franklin did not earn a share of the prize. Read more about DNA.

Continue reading “Birthdays, Nobel Prizes and Basic Research”
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Field Focus: High-Quality Genome Sequences Inform the Study of Human Evolution

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Leafing through my favorite biology textbook from a handful of years ago, I was struck by the relative brevity of the chapter on human evolution. While other fields of biological research have enjoyed a steady gallop of productivity over the last few decades due in part to advances in computing power, imaging technology and experimental methods, the study of human evolution can be seen as having lagged behind until recently due to an almost complete dependence on fossil evidence.

Fortunately, contemporary biology textbook chapters on human evolution are being primed for a serious upgrade thanks to the recent availability of high-quality genome sequences from diverse modern human populations as well as from ancient humans and other non-human hominids, including the Neanderthals and Denisovans (but, for purposes of this story, not the Great Apes).

Modern human skull (left) and Neanderthal skull (right), shown to scale. There are not enough Denisovan bone fragments to reconstruct its skull. Credit: Wikimedia Commons, hairymuseummatt.

What are the new resources for studying human evolution?

The cost of DNA sequencing has dropped precipitously in the last decade. As a result, more complete human genome sequences become available for analysis with each passing year.

For example, the 1000 Genomes Project Exit icon includes more than 1,000 full human genome sequences of individuals from European, Asian, American and Sub-Saharan African populations. Earlier this year, the Simons Genome Diversity Project Exit icon further increased the number of available human genomes by adding 300 individuals representing 142 populations around the globe.

Continue reading “Field Focus: High-Quality Genome Sequences Inform the Study of Human Evolution”
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On this Darwin Day, Evolutionary Geneticist Dr. Dan Janes Discusses the Scientific Contributions of Charles Darwin

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This Sunday, February 12, is Darwin Day—an occasion to recognize the scientific contributions of 19th-century naturalist Charles Darwin. In this video (originally posted on Darwin Day 2016), our own evolutionary geneticist, Dan Janes, answers questions about Darwin and the role of evolution in health and biomedicine.

Continue reading “On this Darwin Day, Evolutionary Geneticist Dr. Dan Janes Discusses the Scientific Contributions of Charles Darwin”

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There’s an “Ome” for That

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In the 13 years since the sequencing of the human genome, the list of “omes” has proliferated. Drop us a comment with your favorite ome—we may feature it in a follow-up post next month.

Have you ever collected coins, cards, toy trains, stuffed animals? Did you feel the need to complete the set? If so, then you may be a completist. A completist will go to great lengths to acquire a complete set of something.

Scientists can also be completists who are inspired to identify and catalog every object in a particular field to further our understanding of it. For example, a comprehensive parts list of the human body—and of other organisms that are important in biomedical research—could aid in the development of novel treatments for diseases in the same way that a parts list for a car enables auto mechanics to build or repair a vehicle.

More than 15 years ago, scientists figured out how to catalog every gene in the human body. In the years since, rapid advances in technology and computational tools have allowed researchers to begin to categorize numerous aspects of the biological world. There’s actually a special way to name these collections: Add “ome” to the end of the class of objects being compiled. So, the complete set of genes in the body is called the “genome,” and the complete set of proteins is called the “proteome.”

Below are three -omes that NIH-funded scientists work with to understand human health.

Genome

Illustration of the entire outer shell of the bacteriophage MS2. Credit: Wikimedia Commons, Naranson.

The genome is the original -ome. In 1976, Belgium scientists identified all 3,569 DNA bases—the As, Cs, Gs and Ts that make up DNA’s code—in the genes of bacteriophage MS2, immortalizing this bacteria-infecting virus as possessing the first fully sequenced genome.

Over the next two decades, a small handful of additional genomes from other microorganisms followed. The first animal genome was completed in 1998. Just 5 years later, scientists identified all 3.2 billion DNA bases in the human genome, representing the work of more than 1,000 researchers from six countries over a period of 13 years. Continue reading “There’s an “Ome” for That”

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Our Complicated Relationship With Viruses

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Illustration of Influenza Virus H1N1. Swine Flu.
Nearly 10 percent of the human genome is derived from the genes of viruses. Credit: Stock image.

When viruses infect us, they can embed small chunks of their genetic material in our DNA. Although infrequent, the incorporation of this material into the human genome has been occurring for millions of years. As a result of this ongoing process, viral genetic material comprises nearly 10 percent of the modern human genome. Over time, the vast majority of viral invaders populating our genome have mutated to the point that they no longer lead to active infections. But they are not entirely dormant.

Sometimes, these stowaway sequences of viral genes, called “endogenous retroviruses” (ERVs), can contribute to the onset of diseases such as cancer. They can also make their hosts susceptible to infections from other viruses. However, scientists have identified numerous cases of viral hitchhikers bestowing crucial benefits to their human hosts—from protection against disease to shaping important aspects of human evolution, such as the ability to digest starch.

Protecting Against Disease

Geneticists Cedric Feschotte, Edward Chuong and Nels Elde Exit icon at the University of Utah have discovered that ERVs lodged in the human genome can jump start the immune system.

For a virus to successfully make copies of itself inside a host cell, it needs molecular tools similar to the ones its host normally uses to translate genes into proteins. As a result, viruses have tools meticulously shaped by evolution to commandeer the protein-producing machinery of human cells.

Continue reading “Our Complicated Relationship With Viruses”
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Interview With a Scientist: Janet Iwasa, Molecular Animator

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The world beneath our skin is full of movement. Hemoglobin in our blood grabs oxygen and delivers it throughout the body. Molecular motors in cells chug along tiny tubes, hauling cargo with them. Biological invaders like viruses enter our bodies, hijack our cells and reproduce wildly before bursting out to infect other cells.

To make sense of the subcutaneous world, Janet Iwasa, a molecular animator at the University of Utah, creates “visual hypotheses”—detailed animations that convey the latest thinking of how biological molecules interact.

“It’s really building the animated model that brings insights,” Iwasa told Biomedical Beat in 2014. “When you’re creating an animation, you’re really grappling with a lot of issues that don’t necessarily come up by any other means. In some cases, it might raise more questions, and make people go back and do some more experiments when they realize there might be something missing.”

Iwasa has collaborated with numerous scientists to develop animations of a range of biological processes and structures Exit icon. Recently, she’s undertaken an ambitious, multi-year project to animate HIV reproduction Exit icon.