Tag: Cool Creatures

Fish Shed Light on Fatherhood in the Animal Kingdom

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Two small gray adult monkeys, one of which has two baby monkeys on its back, on a tree branch. A family of common marmosets. Credit: Francesco Veronesi. CC BY-SA 2.0 Link to external web site.

Fatherhood takes many forms across the animal kingdom. For instance, mammalian fathers are often uninvolved, with only about 10 percent helping to raise their offspring. However, that small percentage of males often makes valuable contributions to their offspring’s upbringing. For instance, cotton-top tamarin and common marmoset dads have the responsibility of carrying babies—which are typically born as sets of twins—almost constantly from birth until independence.

In other groups of animals, fathers are much more likely to share responsibilities with mothers or even act as sole caregivers. Male and female birds contribute equally to raising chicks in most cases. But in rheas and emus—both large, flightless birds—fathers incubate eggs and take care of hatchlings on their own.

And most fish don’t care for their young, but out of the species that do, between one-third and one-half rely on fathers parenting alone. Perhaps the most well-known example is the seahorse, where the male becomes pregnant, carrying his mate’s fertilized eggs in a pouch on his belly until they hatch. Alison M. Bell, Ph.D. Link to external web site, professor of evolution, ecology, and behavior at the University of Illinois at Urbana-Champaign, is investigating paternal care in another fish species where fathers raise offspring solo: the three-spined stickleback. Her work not only helps us understand the value of paternal care for sticklebacks, but also contributes to growing evidence across many species that fatherhood changes males on a physiological level.

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Scientist Interview: Studying the Biochemistry of Insects with Michael Kanost

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Insects vastly outnumber people on our planet. Some are pests, but many are key parts of their ecosystems, and some may even hold secrets for developing new materials that researchers could use in the medical field. Michael Kanost, Ph.D. Link to external web site, a professor of biochemistry and molecular biophysics at Kansas State University in Manhattan, Kansas, has been researching the biochemistry of insects for more than 30 years. His lab studies the tobacco hornworm, a mosquito that carries malaria, and the red flour beetle to better understand insect exoskeletons and immune systems.

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Looking Back at the Top Three Posts of 2019

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Over the past 12 months, we’ve explored a variety of topics in genetics, cell biology, chemistry, and careers in the biomedical sciences. As we ring in the new year, we bring you our top three posts of 2019. If your favorite is missing, let us know what it is in the comments section below!

Amazing Organisms and the Lessons They Can Teach Us

Two Hawaiian bobtail squid with yellow skin, brown spots, and black eyes catching a neon green reflection. Hawaiian bobtail squid. Credit: Dr. Satoshi Shibata.

Studying research organisms, such as those featured in this post, teaches us about ourselves. These amazing creatures, which have some traits similar to our own, may hold the key to preventing and treating an array of complex diseases.

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A Scientist’s Exploration of Regeneration

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Viravuth (“Voot”) Yin, standing with arms crossed and smiling in front of a shelves holding tanks of zebrafish in his lab. Viravuth (“Voot”) Yin, associate professor of regenerative biology and medicine at MDI Biological Laboratory and chief scientific officer at Novo Biosciences, Inc., in Bar Harbor, Maine. Credit: MDI Biological Laboratory.

In 1980, a week after his 6th birthday, Viravuth (“Voot”) Yin immigrated with his mother, grandfather, and three siblings from Cambodia to the United States. Everything they owned fit into a single, 18-inch carry-on bag. They had to build new lives from almost nothing. So, it’s perhaps fitting that Yin studies regeneration, the fascinating ability of some animals, such as salamanders, sea stars, and zebrafish, to regrow damaged body parts, essentially from scratch.

Yin’s path wasn’t always smooth. His family settled in Hartford, Connecticut, near an uncle who had been granted asylum during the Vietnam War. Yin got into a lot of trouble in school, trying to learn a new culture and fit in. Things improved when his mother moved him and his siblings to West Hartford, well known for its strong schools.

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Computational Biologist Melissa Wilson on Sex Chromosomes, Gila Monsters, and Career Advice

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Melissa Wilson wearing a floral dress and speaking beside a podium during her lecture. Dr. Melissa Wilson.
Credit: Chia-Chi Charlie Chang.

The X and Y chromosomes, also known as sex chromosomes, differ greatly from each other. But in two regions, they are practically identical, said Melissa Wilson Link to external web site, assistant professor of genomics, evolution, and bioinformatics at Arizona State University.

“We’re interested in studying how the process of evolution shaped the X and the Y chromosome in gene content and expression and how that subsequently affects literally everything else that comes with being a human,” she said at the April 10 NIGMS Director’s Early-Career Investigator (ECI) Lecture at NIH.

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Amazing Organisms and the Lessons They Can Teach Us

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What do you have in common with rodents, birds, and reptiles? A lot more than you might think. These creatures have organs and body systems very similar to our own: a skeleton, digestive tract, brain, nervous system, heart, network of blood vessels, and more. Even so-called “simple” organisms such as insects and worms use essentially the same genetic and molecular pathways we do. Studying these organisms provides a deeper understanding of human biology in health and disease, and makes possible new ways to prevent, diagnose, and treat a wide range of conditions.

Historically, scientists have relied on a few key organisms, including bacteria, fruit flies, rats, and mice, to study the basic life processes that run bodily functions. In recent years, scientists have begun to add other organisms to their toolkits. Many of these newer research organisms are particularly well suited for a specific type of investigation. For example, the small, freshwater zebrafish grows quickly and has transparent embryos and see-through eggs, making it ideal for examining how organs develop. Organisms such as flatworms, salamanders, and sea urchins can regrow whole limbs, suggesting they hold clues about how to improve wound healing and tissue regeneration in humans.

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Interview with a Scientist: Jeramiah Smith on the Genomic Antics of an Ancient Vertebrate

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The first known descriptions of cancer come from ancient Egypt more than 3,500 years ago. Early physicians attributed the disease to several factors, including an imbalance in the body’s humoral fluids, trauma, and parasites. Only in the past 50 years or so have we figured out that mutations in critical genes are often the trigger. The sea lamprey, a slimy, snake-like blood sucker, is proving to be an ideal tool for understanding these mutations.

The sea lamprey, often called the jawless fish, is an ancient vertebrate whose ancestor diverged from the other vertebrate lineages (fish, reptiles, birds and mammals) more than 500 million years ago. Jeramiah Smith,Link to external web site associate professor of biology at the University of Kentucky, has discovered that lamprey have two separate genomes: a complete genome specific to their reproductive cells, consisting of 99 chromosomes (humans have 23 pairs) and another genome in which about 20 percent of genes have been deleted after development. Using the lamprey model, Smith and his colleagues have learned that many of these deleted genes—such as those that initiate growth pathways—are similar to human oncogenes (i.e., cancer-causing genes).

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Genomic Gymnastics of a Single-Celled Ciliate and How It Relates to Humans

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Laura Landweber
Credit: Denise Applewhite.
Laura Landweber
Grew up in: Princeton, New Jersey
Job site: Columbia University, New York City
Favorite food: Dark chocolate and dark leafy greens
Favorite music: 1940’s style big band jazz
Favorite hobby: Swing dancing
If I weren’t a scientist I would be a: Chocolatier (see “Experiments in Chocolate” sidebar at bottom of story)

One day last fall, molecular biologist Laura Landweber Link to external web site surveyed the Princeton University lab where she’d worked for 22 years. She and her team members had spent many hours that day laboriously affixing yellow Post-it notes to the laboratory equipment—microscopes, centrifuges, computers—they would bring with them to Columbia University, where Landweber had just been appointed full professor. Each Post-it specified the machinery’s location in the new lab. Items that would be left behind—glassware, chemical solutions, furniture, office supplies—were left unlabeled.

As Landweber viewed the lab, decorated with a field of sunny squares, her thoughts turned to another sorting process—the one used by her primary research subject, a microscopic organism, to sift through excess DNA following mating. Rather than using Post-it notes, the creature, a type of single-celled organism called a ciliate, uses small pieces of RNA to tag which bits of genetic material to keep and which to toss.

Landweber is particularly fond of Oxytricha trifallax, a ciliate with relatives that live in soil, ponds and oceans all over the world. The kidney-shaped cell is covered with hair-like projections called cilia that help it move around and devour bacteria and algae. Oxytricha is not only bizarre in appearance, it’s also genetically creative.

Unlike humans, whose cells are programmed to die rather than pass on genomic errors, Oxytricha cells appear to delight in genomic chaos. During sexual reproduction, the ciliate shatters the DNA in one of its two nuclei into hundreds of thousands of pieces, descrambles the DNA letters, throws most away, then recombines the rest to create a new genome.

Landweber has set out to understand how—and possibly why—Oxytricha performs these unusual genomic acrobatics. Ultimately, she hopes that learning how Oxytricha rearranges its genome can illuminate some of the events that go awry during cancer, a disease in which the genome often suffers significant reorganization and damage.

Oxytricha’s Unique Features

Oxytricha carries two separate nuclei—a macronucleus and a micronucleus. The macronucleus, by far the larger of the two, functions like a typical genome, the source of gene transcription for proteins. The tiny micronucleus only sees action occasionally, when Oxytricha reproduces sexually.

Oxytricha trifallax cells in the process of mating
Two Oxytricha trifallax cells in the process of mating. Credit, Robert Hammersmith.

What really makes Oxytricha stand out is what it does with its DNA during the rare occasions that it has sex. When food is readily available, Oxytricha procreates without a partner, like a plant grown from a cutting. But when food is scarce, or the cell is stressed, it seeks a mate. When two Oxytricha cells mate, the micronuclear genomes in each cell swap DNA, then replicate. One copy of the new hybrid micronucleus remains intact, while the other breaks its DNA into hundreds of thousands of pieces, some of which are tagged, recombined, then copied another thousand-fold to form a new macronucleus. Continue reading “Genomic Gymnastics of a Single-Celled Ciliate and How It Relates to Humans”