Study Rules Out Hybridization of Yellow and Pink Iguanas on Wolf Volcano - via Herp Digest

October 15, 2018, Galapagos Conservancy

A recent study ruled out hybridization between the yellow land iguanas (Conolophus subcristatus) and pink land iguanas (C. marthae) that cohabit at the top of the Wolf volcano — revealing that there is no genetic contamination among these two populations.

These results are part of research carried out since 2009 between the Galapagos National Park Directorate  (GNPD) and the Tor Vergara University in Italy on the pink iguanas, which were identified as a new species that year, and on which progress is being made in the knowledge of its biology and ecology.

“This discovery will facilitate the start of a new captive breeding program, since all the individuals selected will be representative of the genetic variability of the species,” said Gabriele Gentile, research associate and project leader.

The same study revealed that on the South Plaza Island there is occasional hybridization between marine iguanas (Amblyrhynchus cristatus) and yellow land iguanas (Conolophus subcristatus), forming infertile first generation individuals. This hybridization is not a cause for concern, since it does not generate movement of genes from one species to another.

“Scientific knowledge is fundamental for the development of management programs and conservation of species, because it allows decisions to be made with the least uncertainty — especially when dealing with fragile ecosystems like those of the Galapagos,” commented Jorge Carrión, director of the GNPD and part of the scientific research team.

Content translated from the Galapagos National Park Directorate, with their permission.

Red and eastern wolves are probably not recent hybrids

Date: June 7, 2017

Source: University of Idaho

A team led by University of Idaho researchers is calling into question a widely publicized 2016 study that concluded eastern and red wolves are not distinct species, but rather recent hybrids of gray wolves and coyotes. In a comment paper that will publish Wednesday, June 7, in the journal Science Advances, the team examines the previous study and argues that its genomic data and analyses do not definitively prove recent hybridization -- but rather provide support for the genetic and evolutionary distinctiveness of red and eastern wolves.

"The history of these species is complex and certainly contains evidence for hybridization in the past. The question is timing," said Paul Hohenlohe, an assistant professor of biological sciences in the UI College of Science and the lead author of the comment paper. "The data and analyses aren't actually a good test of recent vs. older hybridization. In fact, the data are consistent with red and eastern wolves having a long evolutionary history as distinct lineages."

Hohenlohe co-authored the paper with an interdisciplinary team that included co-lead author Linda Rutledge, a research associate in the biology department at Trent University in Ontario, Canada; Lisette Waits, a Distinguished Professor in UI's College of Natural Resources Department of Fish and Wildlife Sciences; UI research scientist Jennifer Adams; UI postdoctoral researcher Kimberly Andrews; and other researchers from Trent, the University of Georgia and Northland College.

Read on 

Bears breed across species borders

Date: April 19, 2017
Source: Senckenberg Research Institute and Natural History Museum

Senckenberg scientists have sequenced the entire genomes of four bear species, making it now possible to analyze the evolutionary history of all bears at the genome level. It shows that gene flow, or gene exchange, between species by extensive hybridization, is possible between most bear species -- not only polar and brown bear. The DNA samples of different bear species came from different European zoos, underlining their importance not only for conservation, but also for research. The study published in Scientific Reports also questions the existing species concept in general, because other genome studies too have, frequently found gene flow among species.

Pizzly, grolars or "capuccino bears" are common names of the offspring resulting from the mating of grizzly bears (Ursus arctos) and polar bears (Ursus maritimus). "Such hybrids among bears are not as rare as we have hitherto assumed," says Prof. Dr. Axel Janke of the Senckenberg Biodiversity and Climate Research Center in Frankfurt. In a large-scale analysis, a team of scientists led by the German evolutionary geneticist has sequenced six complete bear genomes. Each genome is about 2.5 billion base pairs large. "With these new data of the sun bear, sloth bear, Asiatic black bear and spectacled bear, we now have the genomes of all known bear species," adds Janke.

It has previously been assumed that the number of hybrids between polar and brown bears is increasing due to climate change, because brown bears invade northern regions and polar bears move onto the sea ice later than usual. The new results show however that an abundant flow of genes among different bear species occurred to a good deal in the past. Hybrids are thus not necessarily linked to climate change. "Bears can form hybrids in different combinations," explains Janke, and adds: "We knew this from zoos. In the wild, so far this was only observed for polar bears and brown bear as well as Asiatic black and sun bear."

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'Cocktail' orangutans leave researchers shaken and stirred

Reintroduction of genetically distinct subspecies has led to hybridization in an endangered wild population

Date: February 25, 2016

Source: Max-Planck-Gesellschaft

Reintroduction of a genetically distinct subspecies has led to hybridization in an endangered wild orangutan population, report scientists. Inter-breeding animals from two genetically distinct populations can sometimes lead to 'hybrid vigor', in which offspring reap the benefits of their parents' individual qualities, they say.

As their natural habitats continue to be destroyed, increasing numbers of displaced endangered mammals are taken to sanctuaries and rehabilitation centres worldwide. The ultimate goal of these centres is often reintroduction: to return these animals to wild populations. In a new study published in Scientific Reports, however, Graham L Banes and Linda Vigilant of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, caution that such reintroductions can act as a form of genetic translocation. By using genetic analysis to assess a subset of historical reintroductions into Tanjung Puting National Park, Indonesia, they found that orang-utans from a non-native and genetically distinct subspecies were unwittingly released and have since hybridized with the Park's wild population. As orang-utan subspecies are thought to have diverged around 176,000 years ago, with marked differentiation over the last 80,000 years, the researchers highlight the potential for negative effects on the viability of populations already under threat.

When Biruté Galdikas and Rod Brindamour began their pioneering orang-utan rehabilitation efforts at Camp Leakey in Tanjung Puting National Park, Central Kalimantan, all orang-utans were considered a single species. Over 14 years, from 1971 to 1985, they released at least 90 orphaned and displaced apes into the surrounding wild population. Advances in morphological and genetic studies have since revealed two species of orang-utan, however, on the islands of Borneo and Sumatra. The Bornean orang-utan is further subdivided into three distinct, geographically and reproductively isolated subspecies, which last shared a common ancestor in the Pleistocene and have differentiated substantially over tens of thousands of years.

https://www.sciencedaily.com/releases/2016/02/160225135720.htm

Hybridization Between Native And Invasive Species Of Trout Accelerated By Climate Change

USGS

Scientists have discovered that the rapid spread of hybridization between a native species and an invasive species of trout in the wild is strongly linked to changes in climate.

In the study, stream temperature warming over the past several decades and decreases in spring flow over the same time period contributed to the spread of hybridization between native westslope cutthroat trout and introduced rainbow trout – the world’s most widely introduced invasive fish species –across the Flathead River system in Montana and British Columbia, Canada.

Experts have long predicted that climate change could decrease worldwide biodiversity through cross-breeding between invasive and native species, but this study is the first to directly and scientifically support this assumption. The study, published today in Nature Climate Change, was based on 30 years of research by scientists with the U.S. Geological Survey, University of Montana, and Montana Fish, Wildlife & Parks.

Hybridization has contributed to the decline and extinction of many native fish worldwide, including all subspecies of cutthroat trout in western North America, which have enormous ecological and socioeconomic value. The researchers used long-term genetic monitoring data coupled with high-resolution climate and stream temperature predictions to assess whether climate warming enhances interactions between native and nonnative species through hybridization.

Read more at

Rare natural hybridisation results in a dolphin with genetic similarities to both the spinner and striped

January 2014: A newly published study on the clymene dolphin, a small, sleek marine mammal living in the Atlantic Ocean, shows that this species arose through natural hybridisation between two dolphins species. In a molecular analysis including the closely related spinner and striped dolphins, scientists concluded that the clymene dolphin is the product a process that is common for plants, fishes and birds, but quite rare in mammals. 

The study was conducted by to the Wildlife Conservation Society, the American Museum of Natural History , the Mote Marine Laboratory and the University of Lisbon. 

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Human introductions create opportunities for intra-specific hybridization in an alien lizard - via Herp Digest

Sozos Michaelides, Geoffrey M. While, Celia Bell, Tobias Uller

Biological Invasions

May 2013, Volume 15, Issue 5, pp 1101-1112

Abstract

Introduction of individuals from multiple sources could create opportunities for hybridization between previously isolated lineages, which may impact on the invasion process. Identifying the phylogeographic origin of introduced populations is therefore an important task to further test the causes and consequences of human-mediated translocations. The common wall lizard (Podarcis muralis) shows a strong phylogeographic structure as a result of past isolation in glacial refugia, but it has also been commonly introduced outside of its native range. Here we analysed 655 base pairs (bp) of the cytochrome b sequence from 507 individuals from 23 introduced populations of P. muralis in England. We identified 12 unique haplotypes in the introduced populations that were nested into five native geographically distinct clades with genetic divergences ranging from 2.1 to 5.7 %. Multiple clade origin was common within populations, with a maximum of three different haplotype clades being represented within a single population. The genetic data are consistent with a scenario whereby initial establishment was a result of translocation of animals from their native range, whereas more recent establishment (i.e. since the mid-1980s) is the result of translocations of animals from previously established non-native populations. However, this requires further study. Overall, our results show that human introductions have created substantial opportunities for hybridization between genetically and phenotypically distinct lineages, which may have important consequences for the establishment success and long-term viability of introduced wall lizard population

Immediate actions planned to conserve Scottish wildcat

Recent research showed that Scottish wildcat faces extinction within months

September 2012. A range of national actions to save the Scottish wildcat look set to be agreed over the next six months. The move follows the first-ever meeting of a diverse group of land management, research and conservation organisations (see below).

Hybridisation
The main threat to wildcats is hybridisation with feral domestic cats which raises many challenges in correctly identifying wildcats from often fleeting sightings. The first action agreed by the group was an immediate targeted survey to identify the best surviving populations of wildcats. Survey work will be coordinated with the intention of identifying key regions to focus research and conservation actions within.

Translocation
Other possibilities discussed included innovative approaches such as captive breeding and translocation of cats in the wild. However, the current emphasis is to obtain more up to date information on wildcat numbers and distribution which in turn will be used to prioritise action on the ground.

The group aims to have a comprehensive action plan underway by next spring forming a Scotland-wide approach to wildcat conservation overseen by SNH.

Continued:  http://www.wildlifeextra.com/go/news/wildcat-conservation.html#cr