Physical Traits and Genetics in Pigeons

February 15, 2012 by  
Filed under Features

Believed to have been domesticated in the Mediterranean region up to 5,000 years ago, pigeons are providing new insight into the role of genetics in the development of physical traits. A study being carried out by the University of Utah, in the United States, has revealed that there is an enormous amount of diversity among these birds, with more than 350 breeds of pigeons differing in body size, color, patterning, beak size and shape, posture, skeletal structure, vocalizations, flight behavior and feather placement. Enlisting the help of pigeon breeders around the world, the study focused on the visible traits and genetic relationships of 361 pigeons representing 70 domestic breeds, as well as populations on the Isle of Skye in Scotland and Salt Lake City, Utah.

Michael Shapiro, assistant professor of biology at the University of Utah, and the senior author of the study which was published in the journal Current Biology earlier this year, noted that it was observed during the study that similar traits can be found in birds that are distantly related, and conversely, closely related birds can at times look quite different. Among the examples cited to support the study is the fact that both the English trumpeter pigeon and the German owl pigeon have crested head feathers despite not being closely related. Furthermore, English trumpeters have feathers on their feet similar to that of English pouters, and yet the two species are not closely related, as is the case of the short beaks shared by the African owl pigeon and the Budapest short-faced tumbler. On the other hand, the closely related African owl and German owl pigeon have short beaks in common, but the African owl has plain head feathers, with the German owl sporting a head crest.

Other interesting findings of the study include the fact that free-living pigeons, such as those commonly found in cities, particularly around statues, carry the DNA of racing pigeons. Some of the traits found in pigeons are likely as a result of selective breeding, as is the case with other domesticated animals, such as dogs, but many of the traits found in pigeons are as a result of adapting to their environment. Shapiro pointed out that many different animals use the same genes in order to build similar body structures, and if scientists can understand which genes are behind normal diversity in the wild through the study of pigeons, this knowledge could ultimately provide insight into diversity in humans, including human disease.

DNA Research Reveals Lifespan Link

January 17, 2012 by  
Filed under News

Researchers from the Universities of Exeter and Glasgow have determined in a study of the DNA of a captive population of zebra finches (Taeniopygia guttata), that just one specific piece of genetic material in a bird’s cells can reveal how long it is likely to live. Called telomeres, these portions of DNA (deoxyribonucleic acid) which mark the ends of chromosomes are found in almost all higher animals and plants. Telomeres help to protect the ends of chromosomes as they divide, preventing them from fusing with one another, or unraveling. After time, telomere ends become shorter and no longer protect chromosomes, resulting in cell damage and deterioration.

It has long been suspected that telomeres decline and the ageing process are closely linked, but this has not been proven in humans, and studies thus far have relied on limited monitoring during a lifespan. This recent study started measuring telomere length when the zebra finches were twenty-five days old and continued periodically over the course of the birds’ lives. The results, which were published this week in Proceedings of the National Academy of Sciences, revealed a close association between telomere length and longevity. Although the results in this study are very convincing, ecologist Pat Monaghan of the University of Glasgow notes that this does not necessarily hold true for humans, and telomere researcher Duncan Baird of Cardiff University agrees.

Zebra finches were chosen for the study as they breed well in captivity and have an average lifespan of nine years, allowing researchers to draw conclusions in a relatively short space of time when compared to humans, while at the same time not being as short-lived as mice. A total of ninety-nine finches were used in the study and it was noted that the association between lifespan and telomere length was strongest at twenty-five days of age. This is a time in the bird’s life when it is almost fully grown, but still sexually immature and reliant of its parents for sustenance. This age would be roughly equivalent to a prepubescent human.

More research needs to be done to determine the significance of the results, as it is known that telomere length is not exclusively genetically determined and can be shortened by stressful events. Baird also noted that the data doesn’t reveal whether telomeres are driving the ageing process. Moreover, the results were for the entire population of birds being monitored, individual results may present a different picture.

New Genetic Research Turns Bird Families Upside Down

June 30, 2008 by  
Filed under Features

A recent study of bird genetics has researchers startled with surprising new findings. After completing the largest study of bird genetics ever undertaken, U.S. researchers are discovering that a number of birds are not as closely related to similar bird species as was previously thought.

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