The threespine stickleback,Gasterosteus aculeatus, is native to northern Europe, northern Asia, and North America. Most populations are anadromous (they live in seawater but breed in freshwater or brackish water), but there are also freshwater populations confined to landlocked lakes
This species has contributed much to the study of species formation and it is a research organism for evolutionary biologists and geneticists studying adaptation to new environments.
A Hard Look at 3 Myths about Genetically Modified Crops
Superweeds? Suicides? Stealthy genes? The true, the false and the still unknown about transgenic crops
by Natasha Gilbert and Nature magazine
In the pitched debate over genetically modified (GM) foods and crops, it can be hard to see where scientific evidence ends and dogma and speculation begin. In the nearly 20 years since they were first commercialized, GM crop technologies have seen dramatic uptake. Advocates say that they have increased agricultural production by more than US$98 billion and saved an estimated 473 million kilograms of pesticides from being sprayed. But critics question their environmental, social and economic impacts.
Researchers, farmers, activists and GM seed companies all stridently promote their views, but the scientific data are often inconclusive or contradictory. Complicated truths have long been obscured by the fierce rhetoric. “I find it frustrating that the debate has not moved on,” says Dominic Glover, an agricultural socioeconomist at Wageningen University and Research Center in the Netherlands. “The two sides speak different languages and have different opinions on what evidence and issues matter,” he says.
Here, Nature takes a look at three pressing questions: are GM crops fuelling the rise of herbicide-resistant ‘superweeds’? Are they driving farmers in India to suicide? And are the foreign transgenes in GM crops spreading into other plants? These controversial case studies show how blame shifts, myths are spread and cultural insensitivities can inflame debate…
Turtle Genome Analysis Sheds Light On Turtle Ancestry and Shell Evolution
by Science Daily staff
Apr. 28, 2013 — From which ancestors have turtles evolved? How did they get their shell? New data provided by the Joint International Turtle Genome Consortium, led by researchers from RIKEN in Japan, BGI in China, and the Wellcome Trust Sanger Institute in the UK provides evidence that turtles are not primitive reptiles but belong to a sister group of birds and crocodiles. The work also sheds light on the evolution of the turtle’s intriguing morphology and reveals that the turtle’s shell evolved by recruiting genetic information encoding for the limbs…
Zhuo Wang, Juan Pascual-Anaya, Amonida Zadissa, et al. The draft genomes of soft-shell turtle and green sea turtle yield insights into the development and evolution of the turtle-specific body plan. Nature Genetics, 2013; DOI: 10.1038/ng.2615
Ant Family Tree Constructed: Confirms Date of Evolutionary Origin, Underscores Importance of Neotropics
by Science Daily staff
Apr. 22, 2013 — Anyone who has spent time in the tropics knows that the diversity of species found there is astounding and the abundance and diversity of ants, in particular, is unparalleled. Scientists have grappled for centuries to understand why the tropics are home to more species of all kinds than the cooler temperate latitudes on both sides of the equator. Several hypotheses have been proposed to explain the higher species numbers in the tropics, but these hypotheses have never been tested for the ants, which are one of the most ecologically and numerically dominant groups of animals on the planet.
New research by evolutionary biologists Dr. Corrie Moreau of Chicago’s Field Museum and Dr. Charles Bell of the University of New Orleans is helping answer these questions. Their findings are presented this week in the journal Evolution.The scientists used DNA sequence data to build the largest ant tree-of-life to date. This tree-of-life, or family tree of ants, not only allowed them to better understand which ant species are related, but also made it possible to infer the age for modern ants because information from the fossil record in the form of geologic time was included in the research…
The coelacanth isn’t called a “living fossil” for nothing. The 2-meter-long, 90 kg fish was thought to have gone extinct 70 million years ago—until a fisherman caught one in 1938—and the animal looks a lot like its fossil ancestors dating back 300 million years. Now, the first analysis of the coelacanth’s genome reveals why the fish may have changed so little over the ages. It also may help explain how fish like it moved onto land long ago.
“I’m very excited about this paper because coelacanths are animals that we really want to know more about,” says Per Ahlberg, a paleontologist at Uppsala University in Sweden who was not involved with the study.
In order to sequence a coelacanth’s (Latimeria chalumnae) genome, scientists required fresh tissue and blood. That’s no easy task: These fish dwell in deep-sea caves and are exceedingly rare. Only 309 have been spotted in the past 75 years, off the east coast of sub-Saharan Africa and Indonesia. Moreover, caught coelacanths die immediately because of the change in pressure and temperature, and under the hot tropical sun, their DNA quickly degrades…
With its wide-set yellow eyes, oversize ears and long, skeletal fingers, the aye-aye is not Madagascar’s cuddliest-looking lemur. This elusive, nocturnal animal has joined a motley crew of rare animals, including Tasmanian devils, pygmy elephants and many others, whose complete genetic codes, or genomes, researchers have sequenced and analyzed in search of information that might help keep them on the planet.
In a study released today (Mar. 25, 2013) by the journal Proceedings of the National Academy of Sciences, a team sequenced the genomes from 12 aye-ayes from three regions in Madagascar and compared them. They found aye-ayes from one region, in the north of the island country, were genetically distinct from those in western and eastern regions.
The results are important for conservation of the species, researchers say.
“Say something happens with this population up north, we are losing a tremendous amount of total species diversity, which puts this animal at much more risk for extinction,” said Ed Louis, a study researcher and director of conservation genetics at Omaha’s Henry Doorly Zoo and Aquarium…
Though they roam the deep sea around the globe, enigmatic giant squid are all part of the same species, new research finds.
The new study reveals that the genetic diversity of giant squid (Architeuthis) is remarkably low — far lower than that of other marine species examined, said study researcher Tom Gilbert of the University of Copenhagen. The findings suggest that the squid intermingle and mate across the globe.
“The results are extremely surprising,” Gilbert told LiveScience.
Giant squid are mysterious creatures. They dwell in the deep ocean, making them difficult to observe in their natural habitats. In fact, no one had observed a live giant squid in the wild until 2004. The first video of a live giant squid wasn’t released until this year. The animals appear to grow as long as 60 ft (18 m) and are carnivores that prey on fish and other squid…
Water bears, also known as tardigrades, can survive boiling, freezing, the vacuum of space and years of desiccation. Biologist Bob Goldstein, of the University of North Carolina Chapel Hill, describes water bears and explains why he studies them.
Genetic Study of House Dust Mites Demonstrates Reversible Evolution
Mar. 8, 2013
In evolutionary biology, there is a deeply rooted supposition that you can’t go home again: Once an organism has evolved specialized traits, it can’t return to the lifestyle of its ancestors.
There’s even a name for this pervasive idea. Dollo’s law states that evolution is unidirectional and irreversible. But this “law” is not universally accepted and is the topic of heated debate among biologists.
Now a research team led by two University of Michigan biologists has used a large-scale genetic study of the lowly house dust mite to uncover an example of reversible evolution that appears to violate Dollo’s law.
The study shows that tiny free-living house dust mites, which thrive in the mattresses, sofas and carpets of even the cleanest homes, evolved from parasites, which in turn evolved from free-living organisms millions of years ago…
First Large-Scale DNA Barcoding Assessment of Reptiles in the Biodiversity Hotspot of Madagascar, Based on Newly Designed COI Primers 
DNA barcoding of non-avian reptiles based on the cytochrome oxidase subunit I (COI) gene is still in a very early stage, mainly due to technical problems. Using a newly developed set of reptile-specific primers for COI we present the first comprehensive study targeting the entire reptile fauna of the fourth-largest island in the world, the biodiversity hotspot of Madagascar…
Whether fire ants bow to one queen or accept many rulers depends on one long strand of genes, a new study finds.
The gene sequence is the first “social chromosome” ever discovered, according to study researcher Yannick Wurm of Queen Mary, University of London, who called the DNA sequence a “supergene.”
“This was a very surprising discovery,” Wurm said in a statement. “Similar differences in chromosomal structure are linked to wing patterns in butterflies and to cancer in humans, but this is the first supergene ever identified that determines social behavior.”…
As Old as the Hills: Montane Scorpions in Southwestern North America Reveal Ancient Associations between Biotic Diversification and Landscape
by Robert W. Bryson Jr, Brett R. Riddle, Matthew R. Graham ,Brian Tilston Smith, Lorenzo Prendini
The age of lineages has become a fundamental datum in studies exploring the interaction between geological transformation and biotic diversification. However, phylogeographical studies are often biased towards lineages that are younger than the geological features of the landscapes they inhabit.
A temporally deeper historical biogeography framework may be required to address episodes of biotic diversification associated with geologically older landscape changes. Signatures of such associations may be retained in the genomes of ecologically specialized (stenotopic) taxa with limited vagility.
In the study presented here, genetic data from montane scorpions in the Vaejovis vorhiesi group, restricted to humid rocky habitats in mountains across southwestern North America, were used to explore the relationship between scorpion diversification and regional geological history…
A Remarkable Case of Micro-Endemism in the Loatian Rock Rat, Laonastes aenigmamus (Diatomyidae, Rodentia), Revealed by Nuclear and Mitochondrial DNA Sequence Data 
Laonastes aenigmamus is endemic to the limestone formations of the Khammuan Province (Lao PDR), and is strongly specialized ecologically.
From the survey of 137 individuals collected from 38 localities, we studied the phylogeography of this species using one mitochondrial (Cyt b) and two nuclear genes (BFIBR and GHR). Cyt b analyses reveal a strong mtDNA phylogeographical structure: 8 major geographical clades differing by 5–14% sequence divergence were identified, most of them corresponding to distinct karst areas. Nuclear markers display congruent results but with a less genetic structuring.
Together, the data strongly suggest an inland insular model for Laonastes population structure. With 8 to 16 evolutionary significant units in a small area (about 200×50 km) this represents an exceptional example of micro-endemism. Our results suggest that L. aenigmamus may represent a complex of species and/or sub-species. The common ancestor of all Laonastes may have been widely distributed within the limestone formations of the Khammuan Province at the end of Miocene/beginning of the Pliocene. Parallel events of karst fragmentation and population isolation would have occurred during the Pleistocene or/and the end of the Pliocene.
The limited gene flow detected between populations from different karst blocks restrains the likelihood of survival of Laonastes. This work increases the necessity for a strict protection of this rare animal and its habitat and provides exclusive information, essential to the organization of its protection…
Genomes of limpet, leech, and worm put spotlight on lophotrochozoans.
by JADE BOYD
A new report in the journal Nature unveils three of the first genomes from a vast, understudied swath of the animal kingdom that includes as many as one-quarter of Earth’s marine species. By publishing the genomes of a leech, an ocean-dwelling worm and a kind of sea snail creature called a limpet, scientists from Rice University, the University of California-Berkeley and the Department of Energy’s Joint Genome Institute (JGI) have more than doubled the number of genomes from a diverse group of animals called lophotrochozoans (pronounced: LOH-foh-troh-coh-zoh-uhns).
Lophotrochozoans are a diverse group of animals that includes mollusks – such as snails, clams and octopuses — and annelids — such as leeches and earthworms. Like humans and all other animals, lophotrochozoans can trace their evolutionary history to the earliest multicellular creatures. But the lophotrochozoan branch of the evolutionary tree diverged more than 500 million years ago from the branch that produced humans.
Almost all published genomes are from the animal kingdom’s most-studied clades: deuterostomes, which includes humans and other vertebrates, and ecdysozoans, which includes insects. Only two lophotrochozoan genomes have been previously mapped, and both are for parasitic worms, which aren’t representative of most species in the clade…
Although comb jellies seem to be little more than tennis ball-sized blobs in the sea, these organisms are relatively sophisticated in how they use light. The creatures flash a blue-green light at predators, for example, possibly to startle them.
Researchers studying the genome of the comb jelly, also known as a ctenophore, have discovered that the bioluminescent creatures pack in 10 proteins for generating light. They have other proteins called opsins that detect light, even though comb jellies lack eyes, the team reports today in BMC Biology. It’s not clear what the opsins do in this animal. The genome is the first to be sequenced from a bioluminescent animal.
Because ctenophores appear to sit at the base of the animal tree of life, the findings suggest that light-generating and sensing proteins evolved at the same time as multicellularity. Such proteins may have given rise to the diversity of light-sensing molecules seen in animals today, such as in the rods and cones in human eyes. And studying them, the researchers say, could lead to new insights into the origin of eyes and therapies for treating sight disorders.
(via: Science NOW) (photo: Bill Browne, Univ. of Miami)