The Evolution of the Human Genome

Orcas Are Attacking Boats Near Spain. Scientists Don’t Know Why

This Thursday, the Supreme Court restricted the scope of the Clean Water Act pertaining to wetlands, in a 5-4 vote. This could affect the Environmental Protection Agency’s power to protect certain kinds of wetlands, which help reduce the impacts of flooding by absorbing water, and also act as natural filters that make drinking water cleaner. Justice Brett Kavanaugh joined the court’s three liberal members in the dissent, writing that the decision will have, “significant repercussions for water quality and flood control throughout the United States.”

Plus, earlier this month, three orcas attacked a boat, leading to its sinking. This is the third time an incident like this has happened in the past three years, accompanied by a large rise of orcas attacking boats near the Strait of Gibraltar. Scientists are unsure of the cause. One theory is that these attacks could be a fad, led by juvenile orcas in the area, a documented behavior in this subpopulation of the dolphin family. They could also be a response to a potential bad encounter between boats and orcas in the area.

Science Friday’s Charles Bergquist talks with Sophie Bushwick, technology editor for Scientific American, about these and other stories from this week in science news, including a preview of a hot El Niño summer, an amateur astronomer who discovered a new supernova, and alleviating waste problems by using recycled diapers in concrete.

 

 

A Famous Sled Dog’s Genome Holds Evolutionary Surprises

Do you remember the story of Balto? In 1925, the town of Nome, Alaska, was facing a diphtheria outbreak. Balto was a sled dog and a very good boy who helped deliver life-saving medicine to the people in the town. Balto’s twisty tale has been told many times, including in a 1990s animated movie in which Kevin Bacon voiced the iconic dog.

But last month, scientists uncovered a new side of Balto. They sequenced his genes and discovered the sled dog wasn’t exactly who they expected. The study published in the journal Science, was part of a project called Zoonomia, which aims to better understand the evolution of mammals, including our own genome, by looking at the genes of other animals—from narwhals to aardvarks.

Guest host Flora Lichtman talks with Dr. Elinor Karlsson, associate professor in Bioinformatics and Integrative Biology at the UMass Chan Medical School and director of Vertebrate Genomics at the Broad Institute of MIT and Harvard; Dr. Katie Moon, post-doctoral researcher who led Balto’s study; and Dr. Beth Shapiro, professor of ecology and evolutionary biology at UC Santa Cruz, who coauthored the new study on Balto and another paper which identified animals that are most likely to face extinction.

 

 

The Long And Short Of Telomere Activity

Telomeres are repeating short sequences of genetic code (in humans, TTAGGG) located on the ends of chromosomes. They act as a buffer during the cell replication process. Loops at the end of the telomere prevent chromosomes from getting inadvertently stuck together by DNA repair enzymes. Over the lifetime of the cell, the telomeres become shorter and shorter with each cell division. When they become too short, the cell dies. Telomere sequences weren’t thought to do much else—sort of like the plastic tip at the end of a shoelace.

Writing in the Proceedings of the National Academy of Sciences, researchers now argue that telomeres may actually encode for two short proteins. Normally, those proteins aren’t released into the cell. However, if the telomere is damaged—or as it gets shorter during repeated cell replication cycles—those signaling proteins may be able to leak out into the cell and affect other processes, perhaps altering nucleic acid metabolism and protein synthesis, or triggering cellular inflammation.

Jack Griffith, one of the authors of the report and the Kenan Distinguished Professor of microbiology and immunology at the UNC School of Medicine, joins SciFri’s Charles Bergquist to talk about the idea and what other secrets may lie inside the telomere.

 

Philadelphia’s Mütter Museum Takes Down Digital Resources

Robert Pendarvis gave his heart to Philadelphia’s Mütter Museum. Literally.

He has a rare condition called acromegaly, where his body makes too much growth hormone, which causes bones, cartilage and organs to keep growing. The condition affected his heart, so much so that a heart valve leaked. He had a heart transplant in 2020.

Pendarvis thought his original heart could tell an important story, and teach others about this rare condition, which is why he was determined to put it on display at the Mütter Museum.

The Mütter Museum is a Philadelphia institution, a medical museum that draws hundreds of thousands of visitors to its rooms filled with anatomical specimens, models, and old medical instruments. The place is not for the squeamish. Display cases show skulls, abnormal skeletons, and a jar containing the bodies of stillborn conjoined twins.

Pendarvis thought it would be the perfect home for his heart — and more.

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