Could a super snake emerge from Everglades pythons? New DNA study raises possibility

August 23, 2018 by Jenny Staletovich, Miami Herald

What started out as a straightforward genetic study of Florida's invasive python population has turned up a surprising plot twist: a small number of crossbred Burmese and Indian pythons with the potential to become a kind of Everglades super snake.

For the study, published this week in the journal Ecology and Evolution, U.S. Geological Survey researchers examined the tail tissue of 400 snakes captured in South Florida, from the Big Cypress Swamp to the Everglades. While the vast majority appeared to be closely related Burmese pythons—imagine a family reunion packed with first and second cousins—13 had genetic markers from Indian pythons, a subspecies that unlike the swamp-loving Burmese snake prefers high, dry ground.

The number is clearly small, but it raises the risk that over time some Everglades snakes could become better suited to a more varied landscape. Scientists call it hybrid vigor.

"If the Indian pythons have a wider range, perhaps these Everglades snakes now have that capability," said lead author and USGS geneticist Margaret Hunter. "It's quite interesting and quite surprising, but we don't know the extent it's in the population."

Because evolution seems to abhor certainty, there's also the possibility the opposite happens through another process, she said, euphemistically referred to as "outbreeding depression."

The study originally intended to look at the genetic makeup of South Florida snakes to better understand how they spread and how to help control them. Pythons started turning up in the 1980s, likely escapees from a South Dade breeding facility or released pets. By 2000, they were declared official residents in Everglades National Park and have since continued to expand north into the state's expansive water conservation areas and west into Big Cypress. In 2016, they were found breeding in the Keys for the first time.

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DNA study shows dogs have been man’s best friend for 33,000 years

DECEMBER 17, 2015

by Chuck Bednar

Having previously established than humans and canines first made contact roughly 33,000 years ago—most likely in southeastern Asia—scientists are now turning their attentions towards filling in some of the details about the epic journey that turned dogs into “man’s best friend”.

In a paper published this week in the journal Cell Research, experts from the US, China, Canada, Finland, Singapore, and Sweden compared the genomes of 58 different canid species—including a dozen grey wolves, 12 indigenous dogs from northern China, 11 canines from southeast Asia, and four from Nigeria, as well as 19 selectively-bred dogs from various parts of the world.

By comparing the DNA of so many different types of canines, and determining when and where different mutations occurred, they could chart many of the connections and separations that took place throughout the ages, the Guardian and the Los Angeles Times explained on Tuesday.

What they found was that 15,000 years ago—roughly 18,000 years after a gray wolf first made contact with humans in Asia—a small pack of ancestral dogs started migrating to the Middle East, Africa, and Europe, and reached Europe about 10,000 years ago. One group also migrated to the east, breeding with endemic populations in northern China before moving on to the New World.

A more holistic approach to canine evolution

Peter Savolainen, an evolutionary geneticist at the Royal Institute of Technology in Sweden, and his colleagues sequenced the whole genomes of the 46 dog and 12 wolf species that exhibited the highest levels of genetic diversity. Their findings confirmed the date and place of origin, as dogs from East Asia shared more DNA with wolves than those anywhere else on Earth.

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Seabird thought extinct is alive and well

OTAGO, New Zealand, Oct. 4 (UPI) -- A rare seabird scientists had believed to be extinct has been declared alive and well by New Zealand researchers who conducted DNA studies.

Scientists at the University of Otago compared ancient and modern DNA and confirmed the New Zealand storm petrel is still flying in the skies over the island nation, China's official Xinhua news agency reported.

The discovery that the species lives on justifies establishing a program to try to restore the bird's numbers, Otago zoologist Bruce Robertson said.

The researchers began taking blood samples after the first bird thought to be the extinct storm petrel flew into the wheelhouse of a fishing vessel off the east coast of New Zealand in 2003.

They compared DNA with that from three 150-year-old skins of the New Zealand storm petrel collected in the 1800s and held by museums in England and France.

"We found they were one and the same, and these birds are a distinct species of storm petrel," Robertson said in a report published last week.


Read more: http://www.upi.com/Science_News/2011/10/04/Seabird-thought-extinct-is-alive-and-well/UPI-32221317774190/#ixzz1a6OaPa5x

Polar bears traced back to Britain

All polar bears originate from a single ancestor which lived in Britain or Ireland about 50,000 years ago, according to DNA study by scientists. New evidence from fossils found in Irish caves shows that modern polar bars evolved from a single female brown bear at the peak of the last ice age.

Despite the significant differences between polar bears, which are expert swimmers, and brown bears, which are better climbers, the species have often come into contact over the past 100,000 years during periods of unusually hot or cold weather.

A genetic marker carried by every polar bear alive today proves that they all descend from the same female brown bear, who bred with a polar bear to create hybrid offspring.

It had been assumed that this took place in Alaska 14,000 years ago, but now analysis of 242 brown bear and polar bear DNA samples from the past 120,000 years show the hybridisation of the two species occurred much earlier.

Fossils found in Irish caves show that polar bears in fact began carrying the DNA of the female brown bear between 20,000 and 50,000 years ago, before brown bears disappeared from the British Isles.

The study, led by Dr Beth Shapiro of Penn State University in the USA and Prof Daniel Bradley of Trinity College Dublin, was published in the journal Current Biology.

Dr Shapiro said: “Previous research has indicated that the brown bear contributed genetic material to the polar bear's mitochondrial lineage – the DNA that is passed exclusively from mothers to offspring.

“But, until now, it was unclear just when modern polar bears acquired their mitochondrial genome in its present form."

By Nick Collins, Science Correspondent
http://www.telegraph.co.uk/earth/wildlife/8622987/Polar-bears-traced-back-to-Britain.html