Category: Genes

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Cool Image: A Circadian Circuit

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Clock neurons (middle right, right corner and edge), leucokinin (LK) neurons (top left, top right and bottom middle), leucokinin receptor (LK-R) neurons (top left, top right and bottom middle)

This image, taken with a confocal microscope, shows how time-of-day information flows through the fruit fly brain. Clock neurons (stained in blue) communicate with leucokinin (LK) neurons (stained in red at the top left, top right and bottom middle), which, in turn, signal to leucokinin receptor (LK-R) neurons (stained in green). This circuit helps regulate daily activity in the fly. Credit: Matthieu Cavey and Justin Blau, New York University.

Feeling sleepy and dazed after the switch to daylight savings time this weekend? Your internal clocks are probably a little off and need some time to adjust.

Researchers have been studying biological clocks for decades to figure out how they control circadian rhythms, the natural 24-hour pattern of physical, mental and behavioral changes that affect sleep, appetite and metabolism. Knowing more about what makes our clocks tick could help researchers develop better therapies for sleep problems, metabolic conditions and other disorders associated with mistimed internal clocks. Continue reading “Cool Image: A Circadian Circuit”

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Four Ways Inheritance Is More Complex Than Mendel Knew

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Original edition of Gregor Mendel’s 1866 publication, Experiments in Plant Hybridization
An original edition of Gregor Mendel’s 1866 publication, “Experiments in Plant Hybridization,” housed in NIH’s National Library of Medicine. Credit: Alisa Machalek.

This year marks the 150th anniversary of Gregor Mendel’s publication that—after sitting ignored for a few decades—helped launch the field of modern genetics. Mendel didn’t know about DNA. But after painstakingly cross-fertilizing tens of thousands of pea plants over the course of 8 years, this Austrian monk came very close to describing genes.

By picking a species with a handful of visible characteristics that occur in two easily identifiable forms, Mendel was able to pinpoint what he called “factors.” These factors determine traits like a pea’s shape or color, for instance, and are passed down from parents to offspring. He also observed that factors can be dominant or recessive.

Today, we know that inheritance is far more complex than what Mendel saw in his pea plants. Here are some of the things scientists have learned about how traits are passed from one generation to the next. Continue reading “Four Ways Inheritance Is More Complex Than Mendel Knew”

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Evolution and Health: A Conversation with Evolutionary Geneticist Dr. Dan Janes on the Occasion of Charles Darwin’s Birthday

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

For more details about evolution and you, check out our articles Evolution and Health and Everyday Evolution.

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Recognition for CRISPR Gene-Editing Tool

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The CRISPR gene-editing tool was recognized today by Science magazine as its “breakthrough of the year.” We support a number of researchers working in this exciting area and have featured it on this blog. To learn more about this exceptionally promising new method, see below for our illustrated explanation of the CRISPR system and its possible applications.

How the CRISPR System Works

Illustration of CRISPR system

The CRISPR system has two components joined together: a finely tuned targeting device (a small strand of RNA programmed to look for a specific DNA sequence) and a strong cutting device (an enzyme called Cas9 that can cut through a double strand of DNA).

CRISPR system in a cell

Once inside a cell, the CRISPR system locates the DNA it is programmed to find. The CRISPR seeking device recognizes and binds to the target DNA (circled, black).

The Cas9 enzyme cuts both strands of the DNA.

New genetic material incorporated into the broken DNA

Researchers can insert into the cell new sections of DNA. The cell automatically incorporates the new DNA into the gap when it repairs the broken DNA.

CRISPR has many possible uses, including:

  • Insert a new gene so the organism produces useful medicines.
  • Help treat genetic diseases.
  • Create tailor-made organisms to study human diseases.
  • Help produce replacements for damaged or diseased tissues and organs.
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Bacterial Biofilms: A Charged Environment

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Bacillus subtilis biofilm
A Bacillus subtilis biofilm grown in a Petri dish. Credit: Süel Lab, UCSD.

Last summer, we shared findings from Gürol Süel Exit icon and colleagues at the University of California, San Diego, that bacterial cells in tight-knit microbial communities called biofilms expand in a stop-and-go pattern. The researchers concluded that this pattern helps make food at the nutrient-rich margin available to the cells in the starved center, but they didn’t know how. They’ve now shown that the cells use electrochemical signaling to communicate and cooperate with each other.

Because nutrients and other signals cells use to sense each other and their environment move rather slowly, the researchers looked for a faster, more active communication system in biofilms of the bacterium B. subtilis. They focused on electrical signaling via potassium, a positively charged ion that, for example, our nerve and muscle cells use to send or receive signals. Continue reading “Bacterial Biofilms: A Charged Environment”

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Interview With a Worm: We’re Not So Different

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Planarian
Credit: Alejandro Sánchez Alvarado, Stowers Institute for Medical Research.
Schmidtea mediterranea
Home: Freshwater habitats along the Mediterranean
Party trick: Regenerating its head
Most charismatic feature: Eyespots
Work site: Science labs worldwide

The planarian has a power few creatures can match. Remove its head, its tail or nearly any of its body parts, and this aquatic flatworm will simply grow it back. Humans can’t do that, of course. And yet many of the genes that help the planarian regenerate are also found in us. To learn more about this tiny marvel, we “interviewed” a representative. Continue reading “Interview With a Worm: We’re Not So Different”

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Cool Images: A Halloween-Inspired Cell Collection

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As Halloween approaches, we turned up some spectral images from our gallery. The collection below highlights some spooky-sounding—but really important—biological topics that researchers are actively investigating to spur advances in medicine.

Cell Skeleton
Fibroblast
The cell skeleton, or cytoskeleton, is the framework that gives a cell its shape, helps it move and keeps its contents organized for proper function. A cell that lacks a cytoskeleton becomes misshapen and immobile. This fibroblast, a cell that normally makes connective tissues and travels to the site of a wound to help it heal, is lacking a cytoskeleton. Researchers have associated faulty cytoskeletons and resulting abnormal cell movement with birth defects and weakened immune system functioning. See fibroblasts with healthy skeletons.

Continue reading “Cool Images: A Halloween-Inspired Cell Collection”

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Turning Back Every Clock

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Clock
Scientists are studying which genes control biological clock gears and which genes are controlled by them. Credit: Stock image.

When daylight savings time ends this Sunday, we’ll need to adjust every clock in our homes, cars and offices. Our internal clocks will need to adjust too.

The body has a master clock in the brain, as well as others in nearly every tissue and organ. These biological clocks drive circadian rhythms, the physical, mental and behavioral changes we experience on a roughly 24-hour cycle. Your hunger in the morning and sleepiness at night, for example, are caused partly by clock gears in motion. These gears can get out of synch with the day-night cycle when the time changes or when we travel through time zones.

Continue reading “Turning Back Every Clock”

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Cool Image: DNA Origami

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Computer-generated sketch of a DNA origami folded into a flower-and-bird structure.
A computer-generated sketch of a DNA origami folded into a flower-and-bird structure. Credit: Hao Yan, Arizona State University.

This image of flowers visited by a bird is made of DNA, the molecule that provides the genetic instructions for making living organisms. It shows the latest capability of a technique called DNA origami to precisely twist and fold DNA into complex arrangements, which might find future use in biomedical applications.

Continue reading “Cool Image: DNA Origami”
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“Award Season” for Science

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Science award
The biggest prizes each science “award season”: powerful glimpses into fundamental life processes that can yield deeper understanding of health and disease. Credit: Stock image.

Roll out the red carpet and shine up your shoes—it’s “award season” for science. The biggest prizes: powerful glimpses into fundamental life processes that can yield deeper understanding of health and disease.

For instance, the 2015 Albert Lasker Basic Medical Research Award that’s being presented today highlights the seminal work of two scientists on the DNA-damage response, a mechanism that protects the genomes of all living organisms. Chemicals, radiation and duplication errors during cell division are constantly harming our genetic material. Healthy cells respond with a complex network of proteins that work together to mend the damage and halt cell division until repairs are complete. If injury is beyond repair, the proteins trigger cell death. Errors in the DNA-damage response can lead to cancer, neurodegenerative disorders and immune deficiencies.

The scientists recognized today took important steps toward elucidating the mechanics of the DNA-damage response. Evelyn Witkin of Rutgers University established its existence and its basic features in bacteria. Continue reading ““Award Season” for Science”