Failure to account for genetic variation can result in overestimating extinction risk

MAY 6, 2019

by University of Southampton

New research led by the University of Southampton has shown that the threat of range losses for some species as a result of climate change could be overestimated because of the ability of certain animals to adapt to rising temperatures and aridity. The researchers have now developed a new approach to more accurately determine vulnerability, which could aid conservation efforts by ensuring they are focussed on species most at risk. Their findings have been published today in the scientific journal PNAS.

Current methods for assessing vulnerability ignore the potential for some animal populations to adapt genetically to their changing environment, meaning they are able to survive in warming temperatures and drier conditions better than other populations within the same species.

The international team was led by Dr. Orly Razgour, lecturer in Ecology at the University of Southampton, and studied the genomic data of two species of bats native to the Mediterranean, an area which is particularly affected by rising global temperatures.

Read on

How the lion lost its strength: big cats’ survival at risk as DNA defences dwindle

The legacy of colonial hunting has made the king of beasts genetically feebler and more vulnerable

Robin McKie

Sat 30 Mar 2019 15.00 GMTLast modified on Sat 30 Mar 2019 20.40 GMT

For more than a century, explorers and settlers have warned about the likely impact of the hunting of lions and other wild animals in Africa. One of the most prescient, Frederick Selous, the inspiration for the character Allan Quatermain in the novels of H Rider Haggard, wrote in 1908 that “since my first arrival in 1871, I had seen game of all kinds gradually decrease and dwindle in numbers to such an extent that I thought that nowhere south of the Great Lakes could there be a corner of Africa left where the wild animals had not been very much thinned out”.

Now researchers have uncovered the impact of that predation on the lion. Lion numbers and range have plunged – but it appears their genetic fitness has also declined. An alarming new study has revealed that lions shot by colonial hunters more than 100 years ago were more genetically diverse than the ones that now populate Africa. The discovery is worrying because it indicates that the species’ fight to survive may be even more difficult than had been previously thought.

“Loss of genetic diversity means that lions are now less able to withstand new diseases or environmental problems, such as heatwaves or droughts,” said lead author Simon Dures, of the Zoological Society of London. “It means that we will have to be even more careful about how we try to protect them.”

Increased parcelling of land by farmers makes it harder for lions to interact, further reducing their genetic diversity

In the late 19th century there were about 200,000 members of Panthera leo roaming the savannahs of Africa. Then European colonialists arrived and began shooting lions – the most social of all cats – in their thousands, first as sport and later to protect the cattle that the newcomers had begun to farm. With fewer than 20,000 of these majestic predators left on the continent, the species has now been designated as “vulnerable”.

Continued

A single gene turns socially organized bees into social parasites

January 23, 2019, Martin-Luther-Universität Halle-Wittenberg

A small change in the genetic makeup of the South African Cape bee turns the socially organised animal into a fighting parasite. This change ensures that infertile worker bees begin to lay their own eggs and fight other colonies. In the current issue of the journal Molecular Biology and Evolution, an international research team led by Martin Luther University Halle-Wittenberg (MLU) outlines for the first time the genetic basis for this rare phenomenon.

Bees are social insects that live together in large colonies with a distinct social structure. Usually, roles are clearly distributed within a bee colony: In addition to male drones, there are numerous infertile female worker bees that care for the nest and provide for the queen. The queen is solely responsible for producing the colony's entire offspring, with the male drones developing from her unfertilised eggs and female bees from the fertilised ones. New queens only emerge when the colony divides or when the previous queen has died or is too old to continue to produce new offspring.

The situation is different for the South African Cape bee. Some of its worker bees are able to produce female offspring from unfertilized eggs. After the animals have been raised in their own colony, the false queens begin to reproduce more of their kind and can invade foreign but closely related bee colonies and ultimately take over their hives. The behaviour was first observed in the 1990s by beekeepers trying to establish the Cape bee in a region of South Africa where another honeybee subspecies lived.

Read more at: 

Genetics of California mountain lions: Research to inform future conservation

Date:  December 21, 2018

Source:  University of Wyoming

Fragmentation of wildlife populations is increasing on a global scale, and understanding current genetic structure, genetic diversity and genetic connectivity is key to informing future wildlife management and conservation.

This is true of mountain lion -- also known as pumas or cougars -- populations in California, according to a new study conducted by a University of Wyoming research team.

"Large expanses of continuous habitat provide populations the opportunity to maintain large numbers of gene variants, called alleles. This is analogous to a deck of cards. If you have 40 cards, you are capable of harboring more types of cards than if you had 10," says Kyle Gustafson, an assistant professor of genetics in the Department of Biology and Environmental Health at Missouri Southern State University, but who started this work in Holly Ernest's Wildlife Genomics and Disease Ecology Lab at UW. "When populations get isolated, like many of the puma populations surrounded by urbanization, the only way for them to maintain a large number of alleles is through migration. Otherwise, natural selection and genetic drift will ultimately lead to genetic uniformity (fixation) and mating among related individuals (inbreeding)."

The new study, titled "Genetic Source-Sink Dynamics Among Naturally Structured and Anthropogenically Fragmented Puma Populations," was published Dec. 10 in Conservation Genetics, a journal that promotes the conservation of biodiversity by providing a forum for data and ideas, aiding the further developments of this area of study. Contributions include work from the disciplines of population genetics, molecular ecology, molecular biology, evolutionary biology, systematics and forensics.

Read  more  

Common genetic toolkit shapes horns in scarab beetles

Rhinoceros beetles and dung beetles use the same genes to form their elaborate horns

Date:  October 4, 2018

Source:  PLOS

Horns have evolved independently multiple times in scarab beetles, but distantly related species have made use of the same genetic toolkit to grow these prominent structures, according to a study publishing October 4, 2018 in the open-access journal PLOS Genetics by Teruyuki Niimi at the National Institute for Basic Biology in Okazaki, Japan, and colleagues.

There are over 35,000 species of scarab beetle (Scarabaeidae), and many scarab beetles grow horns on the head and/or upper body. Horns are considered to be independent radiation in rhinoceros beetles and their distant relatives dung beetles. Rhinoceros beetles include some of the largest insect species on earth, such as the famous Atlas and Hercules beetles. To investigate the genetic mechanisms that control horn development in these distant groups, the team examined gene expression and function in early horn cells in developing larvae of the Japanese rhinoceros beetle (Trypoxylus dichotomus), and compared this with published data for dung beetles.

Continued  

Killer whale genetics raise inbreeding questions

Endangered orca population in Washington acts genetically smaller than it really is

Date:  April 24, 2018

Source:  NOAA Fisheries West Coast Region

A new genetic analysis of Southern Resident killer whales found that two male whales fathered more than half of the calves born since 1990 that scientists have samples from, a sign of inbreeding in the small killer whale population that frequents Washington's Salish Sea and Puget Sound.

Only about 26 of the 76 endangered whales in the Southern Resident population are currently breeding, according to the analysis published this week in Animal Conservation. The limited number of breeding whales reduces the effective size of the population, leaving it less resilient to change and possibly compromising the survival of individual animals, said lead author Michael Ford, a conservation biologist at NOAA Fisheries Northwest Fisheries Science Center in Seattle.

"The effective size of this population is really small," he said. "It's acting like a population of only 20-30 individuals."

Authors of the research also include scientists from the North Gulf Oceanic Society and Center for Whale Research. While the new paper builds on earlier genetic studies, it also raises new questions about whether inbreeding may be contributing to the population's struggles. Southern Resident numbers have fallen to their lowest point in 30 years.

Continued  

New genetic research shows extent of cross-breeding between wild wolves and domestic dogs

Date:  March 21, 2018

Source:  University of Lincoln

Mating between domesticated dogs and wild wolves over hundreds of years has left a genetic mark on the wolf gene pool, new research has shown.

The international study showed that around 60 per cent of Eurasian grey wolf genomes carried small blocks of the DNA of domestic dogs, suggesting that wolves cross-bred with dogs in past generations.

The results suggest that wolf-dog hybridisation has been geographically widespread in Europe and Asia and has been occurring for centuries. The phenomenon is seen less frequently in wild wolf populations of North America.

Researchers examined DNA data from grey wolves -- the ancestors of the domestic dog -- to determine how much their gene pool was diluted with the DNA of domestic canines, and how widespread the process of hybridisation is.

Despite the evidence of hybridisation among Eurasian grey wolves, the wolf populations have remained genetically distinct from dogs, suggesting that such cross-breeding does not diminish distinctiveness of the wolf gene pool if it occurs at low levels.

The results could have important conservation implications for the grey wolf, which is a keystone species -- meaning it is vital to the natural balance of the habitat it occupies. The legal status of hybrids is still uncertain and unregulated.

The study was led by researchers from the University of Lincoln, UK, the Italian National Institute for Environmental Protection and Research and the University of California, Los Angeles.

Dr Malgorzata Pilot, from the School of Life Sciences at the University of Lincoln, said: "The fact that wild wolves can cross-breed with dogs is well-documented, but little was previously known about how widespread this phenomenon has been and how it has affected the genetic composition of wild wolf populations.

Read more

Genetic study shakes up the elephant family tree

Date: June 6, 2017

Source: University of Illinois at Urbana-Champaign

New research reveals that a species of giant elephant that lived 1.5 million to 100,000 years ago -- ranging across Eurasia before it went extinct -- is more closely related to today's African forest elephant than the forest elephant is to its nearest living relative, the African savanna elephant.

The study challenges a long-held assumption among paleontologists that the extinct giant, Palaeoloxodon antiquus, was most closely related to the Asian elephant. The findings, reported in the journal eLife, also add to the evidence that today's African elephants belong to two distinct species, not one, as was once assumed.

Understanding their genetic heritage is key to keeping today's elephants from going extinct, said University of Illinois animal sciences professor Alfred Roca, a co-author of the new study. Roca led research in the early 2000s that provided the first genetic evidence that African elephants belonged to two distinct species. Subsequent studies have confirmed this, as does the new research.

"We've had really good genetic evidence since the year 2001 that forest and savanna elephants in Africa are two different species, but it's been very difficult to convince conservation agencies that that's the case," Roca said. "With the new genetic evidence from Palaeoloxodon, it becomes almost impossible to argue that the elephants now living in Africa belong to a single species."

Continued 

Scientists studying dolphins find Bay of Bengal a realm of evolutionary change

Genetic research on Indo-Pacific bottlenose, humpback dolphins finds animals distinct from neighboring populations

Date: December 15, 2016

Source: Wildlife Conservation Society

Marine scientists have discovered that two species of dolphin in the waters off Bangladesh are genetically distinct from those in other regions of the Indian and western Pacific Oceans, a finding that supports a growing body of evidence that the Bay of Bengal harbors conditions that drive the evolution of new life forms, according to a new study by the American Museum of Natural History(AMNH), WCS (Wildlife Conservation Society), and the cE3c -- Centre for Ecology, Evolution and Environmental Changes (Universidade de Lisboa).

In the comparative study using DNA collected from both Indo-Pacific humpback dolphins (Sousa chinensis) and Indo-Pacific bottlenose dolphins (Tursiops aduncus) and data from previous genetic studies, the authors of a newly published paper inConservation Genetics have found that both populations of both species are distinct from populations in other parts of the Indian Ocean and western Pacific. This discovery follows the recent description of a possible new species of "river shark" in the same waters.

The authors of the study titled "Oceanic drivers of population differentiation in Indo-Pacific bottlenose (Tursiops aduncus) and humpback (Sousa spp.) dolphins of the northern Bay of Bengal" are: Dr. Ana R. Amaral of cE3c, Universidade de Lisboa, Portugal and AMNH's Sackler Institute of Comparative Genomics; Brian D. Smith and Rubaiyat M. Mansur of WCS; and Dr. Howard C. Rosenbaum of WCS and affiliated with AMNH.

Continued

Scientists uncover genetic evidence that 'we are what we eat'

Date: November 15, 2016

Source: University of Oxford

Researchers at the University of Oxford have demonstrated that the diets of organisms can affect the DNA sequences of their genes.

In a study on two groups of parasites, the team detected differences in DNA sequences that could be attributed to the composition of their food.

The results are published in the journal Genome Biology.

Study co-author Dr Steven Kelly, from Oxford's Department of Plant Sciences, said: 'Organisms construct their DNA using building blocks they get from food. Our hypothesis was that the composition of this food could alter an organism's DNA. For example, could a vegetarian panda have predictable genetic differences from a meat-eating polar bear?

'To test this hypothesis, we picked simple groups of parasites to use as a model system. These parasites share a common ancestor but have evolved to infect different hosts and eat very different foods.

'We found that different levels of nitrogen in a parasite's diet contributed to changes in its DNA. Specifically, parasites with low-nitrogen, high-sugar diets had DNA sequences that used less nitrogen than parasites with nitrogen-rich, high-protein diets.'

The study involved groups of eukaryotic parasites (Kinetoplastida) and bacterial parasites (Mollicutes) that infect different plant or animal hosts.

Read on  https://www.sciencedaily.com/releases/2016/11/161115111720.htm