Alternative Evolution: Why Change Your Own Genes When You Can Borrow Someone Else's?

/PRNewswire/ -- It has been a basic principle of evolution for more than a century that plants and animals can adapt genetically in ways that help them better survive and reproduce.

Now, in a paper to be published in the journal Science, University of Rochester biologist John Jaenike and colleagues document a clear example of a new mechanism for evolution. In previous well documented cases of evolution, traits that increase an animal's ability to survive and reproduce are conferred by favorable genes, which the animal passes on to its offspring.

Jaenike's team has chronicled a striking example of a bacteria infecting an animal, giving the animal a reproductive advantage, and being passed from mother to children. This symbiotic relationship between host animal and bacteria gives the host animal a readymade defense against a hazard in its environment and thus has spread through the population by natural selection, the way a favorable gene would.

Jaenike provides the first substantial report of this effect in the wild in his paper "Adaptation via Symbiosis: Recent Spread of a Drosophila Defensive Symbiont," but he says it may be a common phenomenon that has been happening undetected in many different organisms for ages.

Aside from shedding light on an important evolutionary mechanism, his findings could aid in developing methods that use defensive bacteria to stave off diseases in humans.

Jaenike studied a species of fly, Drosophila neotestacea, which is rendered sterile by a parasitic worm called a nematode, one of the most abundant, diverse, and destructive parasites of plants and animals in the world. Nematodes invade female flies when they are young by burrowing through their skin and prevent them from producing eggs once they mature. However, when a female fly is also infected with a bacteria species called Spiroplasma, the nematodes grow poorly and no longer sterilize the flies, Jaenike found. He also discovered that, as a result of the Spiroplasma's beneficial impact, the bacteria have been spreading across North America and rapidly increasing in frequency in flies as they are passed from mother to offspring. Testing preserved flies from the early 1980s, Jaenike found that the helpful bacteria were present in only about 10% of flies in the eastern United States. By 2008, the frequency of Spiroplasma infection had jumped to about 80%.

"These flies were really getting clobbered by nematodes in the 1980s, and it's just remarkable to see how much better they are doing today. The spread of Spiroplasma makes me wonder how much rapid evolutionary action is going on beneath the surface of everything we see out there," Jaenike said.

He reasoned that the substantial increase in Spiroplasma infection was an evolutionary response to the recent colonization of North America by nematodes. As the nematodes invaded the continent, the bacteria proved to be a convenient and potent defense against the nematodes' sterilizing effect. Now, the majority of flies in eastern North America carry the bacteria, and the bacterial infection appears to be spreading west. Without any mutation in their own genes, the flies have rapidly developed a defense against an extremely harmful parasite simply by co-opting the genetic material of another organism and passing it on from generation to generation.

"This is a beautiful case showing that the main reason these Spiroplasma are present in these flies is for their defensive role," said Nancy Moran, the Fleming Professor of Ecology and Evolutionary Biology at Yale University. Moran studies the role of defensive symbionts in aphids. "These heritable symbionts are a way for an animal host to acquire a new defense very quickly. One way to get a truly novel defense is to get a whole organism rather than mutating your own genes that aren't that diverse to begin with."

Jaenike's work could also have implications for disease control. Nematodes carry and transmit severe human diseases, including river blindness and elephantiasis. By uncovering the first evidence of a natural, bacterial defense against nematodes, Jaenike's work could pave the way for novel methods of nematode control. He plans to investigate that prospect further.

Jaenike's coauthors on the paper are Robert Unckless and Lisa Boelio from the University of Rochester, and Steve Perlman and Sarah Cockburn from the University of Victoria in British Columbia. The work was funded by the National Science Foundation.

-----
www.fayettefrontpage.com
Fayette Front Page
www.georgiafrontpage.com
Georgia Front Page
Follow us on Twitter:  @GAFrontPage

For Pet Owners, Share Valentine's Day Love With Hugs, but Skip the Hearts and Flowers for Fido and Tabby

PRNewswire -- On Valentine's Day we profess our unconditional love to those who mean the most, lavishing them with affections and confections. For animal lovers, expressions of adoration and devotion can easily extend to our pets.

However, there are some pet hazards associated with the traditions of the holiday, explains veterinarian Dr. Kristie Souders of North Shore Animal League America, the world's largest no-kill animal rescue and adoption organization. Dr. Souders offers these tips on how to keep pets safe from potential Valentine's Day hazards.

Chocolate

The number one belly ache for pets on Valentine's Day is chocolate since it's so readily available. Depending on the amount ingested, chocolate is potentially poisonous to many animals. A good rule of thumb to remember is the less sweet the chocolate, the more toxic it could be. These particular chocolates contain theobromine, which is a substance similar to caffeine. Even in small, non-toxic doses, chocolate can still cause stomach upset, diarrhea, vomiting, hyperactivity, dehydration and seizures. It's best not to tempt fate with tempting chocolates. Leave the sweets for your human sweetie.

Candy and Gum

Many sugar-free candy, gum and baked products today contain xylitol. Xylitol is a sweetener found in plants that is used as a sugar substitute and is highly toxic to dogs, so be sure not to leave these snacks where your pet can find them. Dogs ingesting significant amounts of gum or candies solely or largely sweetened with xylitol may develop a fairly sudden drop in blood sugar, resulting in depression, vomiting, loss of coordination, seizures and even liver failure. Symptoms come on very quickly. If you suspect that your pet has ingested any amount of xylitol, call your veterinarian immediately.

Plants, Flowers and Candles

Many flower and plant varieties are poisonous or harmful to pets. Different plants and flowers have varied effects. Some of the more popular varieties that may be found around Valentine's Day are: Baby's Breath, Chrysanthemums, Daffodils, various Lilies, Ferns, Hyacinth, Hydrangea, Impatiens, Lily-of-the-Valley, Rubber plants, and Tulips. Cats, especially, find grass-like plants irresistible and have access to just about everywhere. There are many more flowers and plants that can cause upset and even death to your pet, so please be aware to keep all varieties of flora and fauna away from them. Candles are also popular on holidays. Be mindful that pets, especially cats, can be attracted to the flicker and have the potential for being burned or knocking over a candle that could cause a fire. Keep burning candles out of reach and never leave them unattended when your pet is in the area.

Pamper Your Pets This Valentine's Day

While traditional Valentine's Day goodies are not good for animals, there are plenty of pet delicacies you can use to pamper your pet so he doesn't feel left out. An extra long walk or a special brushing can be just what Cupid ordered. Exercise and grooming have infinite benefits for both of you. Treats of the non-edible kind are equally as satisfying. A new bed, toy, catnip or bone can help express that special place in the heart saved for our furry friends.

This Valentine's Day, if you are an animal lover, think about opening your heart and home to a shelter animal. You will be saving a life. If you don't have a pet, consider the Valentine's gift of sponsorship. For more information on pet safety and well-being, to learn more about North Shore Animal League America, or to send a Valentine's e-card visit www.AnimalLeague.org .

-----
www.fayettefrontpage.com
Fayette Front Page
www.georgiafrontpage.com
Georgia Front Page
Follow us on Twitter:  @GAFrontPage

Comment Sought on New Invasives Species Plan

A draft plan that targets more than 180 invasive species threatening Georgia’s rich variety of native wildlife is available for public comment.

The Georgia Invasive Species Strategy describes the complex scope of problems posed by non-native plants, animals and disease-causing organisms and proposes ways to lessen the impacts in a state ranked sixth in the nation in biological diversity.

Jon Ambrose, assistant chief of the Georgia Wildlife Resources Division’s Nongame Conservation Section, said the strategy provides a framework that will help communicate and coordinate invasive species management priorities.

“There are a lot of organizations that are active in this area. The Invasive Species Strategy is intended to provide a picture of where we are now and where we want to go in the future,” Ambrose said.

Copies are available at www.georgiawildlife.com (click the “Conservation” tab to reach the link) or from the Georgia Wildlife Resources Division office in Social Circle (770-761-3035). A public comment meeting is set for 5:30-7:30 p.m. Feb. 12 at the Wildlife Resources Division’s Conservation Center in Social Circle. For directions, go to www.georgiawildlife.com.

The deadline to submit comments is Feb. 16. Send written comments to jon.ambrose@gadnr.org or Jon Ambrose, Georgia Wildlife Resources Division, 2070 U.S. Highway 278 S.E., Social Circle, Ga.30025.

Invasives are plants and animals accidentally or intentionally introduced outside their natural ranges and which cause harm to the environment, economy or even human health. For example, laurel wilt, a fungal disease spread by an ambrosia beetle that is not native to the U.S., is killing redbay trees and related species in the Southeastern Coastal Plain. Redbays are a food source for birds and deer, and a critical host plant for the Palamedes swallowtail butterfly.

Cogongrass, another priority invasive species, is an aggressive, colony-forming grass that chokes out native plants and is spreading across the region. The Georgia Forestry Commission has established a statewide Cooperative Weed Management Area and Task Force to help control cogongrass.

The draft Invasive Species Strategy, compiled by an advisory committee representing about 30 public agencies and non-governmental organizations, summarizes what is being done to combat invaders, identifies gaps in current programs, and recommends improvements. Objectives are aimed at guarding against the influx of more non-native species and minimizing the threat of those already here.

The Georgia Invasive Species Advisory Committee listed 51 invasive or potentially invasive plant species, 107 animals and 30 disease-causing organisms.

Next steps could include funding for an invasive species coordinator, development of new educational materials and formation of a rapid response plan for priority species.

The overriding goal of the work started in August 2007 is enhancing collaboration among invasive species efforts statewide, which will increase effectiveness and options for funding.

The Invasive Species Strategy follows on the heels of a related document that deals with aquatic exotics and was also compiled by the advisory committee. The Georgia Aquatic Nuisance Species Management Plan is being reviewed by a federal task force before being finalized.

Both plans build on current efforts of groups such as the Georgia Invasive Species Task Force to identify high-priority species, assess impacts and threats, implement control methods, and educate the public about the environmental and economic impacts of invasive species.

Georgia’s Wildlife Action Plan, the conservation blueprint for the state Department of Natural Resources, rates invasive species a major threat to biodiversity and lists development of a statewide plan to monitor and control them as a high priority. On a national scale, the economic losses and environmental damage caused by exotic species total approximately $120 billion a year.

-----
www.fayettefrontpage.com
Fayette Front Page
www.georgiafrontpage.com
Georgia Front Page