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Monday 30 January 2012

Gene Discovered- Kendria Shifflett

Blindness-Causing Disease Gene Discovered

University of Pennsylvania veterinarians, vision-research scientists, and associates at Cornell University have finally found a gene that is the cause of blindness in dogs. They have been researching the cause for mare than three decades. In the late 1960s, Aguirre was studying a genetic disease that was causing for this rare dog breed to have a blindness disorder. The rare dog type is the Norwegian Elkhound. Aguirre cured those dogs, he then researched more to find other dogs with the same condition. The dogs conditions were similar only to find out that these other dogs have another type of disease. This disease in these dogs was Early Retinal Degeneration also known as ERD. The ERD disease happened earlier in the dogs life. Instead of the dog being two or four, these dogs were going blind within a year of birth. Aguirre and his colleagues looked into gene therapies to narrow down the list. They found the gene hidden into the dog’s genome. Genome is an organism’s hereditary information. The gene that causes blindness in the dogs was least expected because this particular gene is the dog’s brain. Aguirre didn’t think this gene had anything to do with vision, but he is proven wrong. This gene is important to the retina. In the retina there are visual cells, but when the dog has Early Retinal Degeneration the cells are lost and the vision fades. Retinas from dogs with ERD shows that during a period called plateau, the vision cells die but they are quickly replaced. Researchers found that the photoreceptors were being affected. Photoreceptors are cells that are used to sense or receive light. The article states that there are two different types of cells that are for vision, which helps us to see lights, colors, etc. Humans have three different types of cones that helps us make out colors, dogs only have two cones. Their cones are used for short wavelength and then the other cone is used for long and medium wavelength. The researchers used an antibody-labeling system to see what was happening to the photoreceptors. When looking into the antibody-labeling system they in the short wavelength cone a lot of rods were labeled also. The cell had hybrid photoreceptor. Researchers don’t know exactly what the gene does but they guess it is involved with control of the cell division cycle. In the retina, photoreceptor cells quit dividing after birth, but the hybrid photoreceptor cells continue to divide. The hybrid photoreceptor cells divide in the plateau period. Aguirre and his colleagues are studying this disease to under stand photoreceptor cells divide. They are trying to find a way to take control over the gene so they can get the division component without the abnormal component.
The science behind the article is the discovery that a gene was actually causing the blindness in the dogs. I thought this article was interesting because I never thought a gene could make someone go blind. It also interested me because it had a lot to do with dogs and I want to be a veterinarian. This article really interested me, I like finding out new things dealing with animals.

Work Citied
University of Pennsylvania. "New twist in a blindness-causing disease gene discovered." ScienceDaily, 21 Sep. 2011. Web. 19 Jan. 2012.

Summary of Genetic Predictions of Racing Performance in Quarter Horses

Summary of Genetic Predictions of Racing Performance in Quarter Horses
By: R. L. Willham and D. E. Wilson

The purpose of this article is to find what genetic traits can be used to predict what quarter horses will be best race horses. This information is then given to the breeders in order to produce the top notch race horses for competition. The researchers behind this data were from Iowa State University and Texas Tech University. These researchers were supported by the American Quarter Horse Association(AQHA). The idea of this research was to understand the genetics of breeding these quarter horses in order to select the ultimate horses to be selected to breed for the breed program. These researchers started out by selecting and studying horses that had won previous halter showing awards at the national level. Although halter showing is different from racing, these researchers claimed to have gain knowledge about racing from studying these halter showing winners. In 1985, these researchers started concentrating more deeply on racing performance.

Over one million racing records were studied and there was found to be a linear correlation between the horses race times and distance. Sex, age, and weight were some factors that were taking into consideration when analyzing these records. Stallions, mares, geldings, and nonparent horses were evaluated at three distances. The information gathered was compounded of these horse’s breeding values and race effects to determine the horse’s phenotypes, genotypes, and environmental trends. From this information genetic trend in these horses decrease race times were found through the years of 1976- 1979.

The next analysis done on genetic racing predictions included a number of stallions, mares, and their progeny. The horses were listed in breeding value order according to the fastest horses, to the slowest. Information that was recorded about each horse was they name, registration number, birth year, number of races run, their progeny, and number of progeny races, horse value, and the breeding value. The results from this analysis were not really that surprising. This means that the system of ranking the stallions what efficient enough to get correct results. The offspring is what these researchers found interesting, because they could then predict which quarter horse would be the best racing horse and these were the horses that were the future of the racing industry.

Today breeding the ultimate race horse has become somewhat of an art form. The association produced the data from all the horses that race and display this information to all the quarter horse breeders. This knowledge of breeding the ultimate race horses and the factors that go into the best race horses have enhanced the sport of horse racing tremendously. Genetic predictions of horse sped is just one aspect of many that has been researched about these race horses.
The importance of this article is that horse racing is a national sport that people spend millions, maybe even billions of dollars each year, to keep the excitement, and competitiveness of this sport going. This genetic research has only enhanced these races and amped up the competition. The breeders bred the fastest horses with the other fastest horses. There are many factors that go into calculating the superior racing horse, but that’s what this research is all about.

Hannah Shumaker
01/30/12

Wednesday 25 January 2012

The Genetics and Characterization of an Open Flower Mutant in Chickpea

THE GENETICS AND CHARACTERIZATION OF AN OPEN FLOWER MUTANT IN CHICKPEA

Cicer arietinum, also known as the chickpea, is a self-pollinated grain legume from the family Fabaceae, making it a type of seed or pod. When the chickpea plant is in its flowering stage, normally the petals completely enclose the reproductive organs (stamen and gynecium). And the stamens are in a diadelphous condition where 9 out of its 10 stamens are fused and 1 remains free. Recently, however, an open-flower mutant (called OFM-3) was identified that did not have its organs enclosed by petals and all 10 of its stamens were free instead of the normal 9 free 1 fused ratio.

In years past many mutations have occurred in the hybridization of chickpeas, some spontaneous and others induced. Two other open-flower mutants, like OFM-3, have occurred over the years and have been studied. These two mutants are designated as ICC 16341 and ICC 16129. In this study of the mutant chickpea a team of researchers in International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), OFM-3 was crossed with the ICC 16341 and ICC 16129 open-flower mutants in order to determine OFM-3’s patterns of inheritance. Aside from the open flower trait and free stamens other traits were studied such as pod yield, growth habits, and pollen fertility.

When the growth habits of OFM-3 were studied it was found to have light pink flowers, normal green leaves, and a weak main stem that grew horizontally over the soil. Its flower structure was considered unique in comparison to a normal closed flower plant, but it was also different from the ICC 16341 and ICC 16129 types. Like a standard flower OFM-3 had 5 petals but they were all free (open instead of closed) like the other two mutant varieties, but its petal size was larger than that of the two. However, OFM-3 was similar to ICC 16341 in that all 10 stamens were free instead of 9 fused and 1 free.

One of the oddest traits of OFM-3 was that in 73% of the pods seeds did not develop, meaning there was only 27% seed development. This was very low in comparison to ICC 16341 and ICC 16129 which both had seed development rates over 50%. In all three years of the crop growth period OMF-3 consistently had a low seed rate, so it could not have been due to factors in the environment. It was possible that pollen sterility could have contributed to the lack of seeds, but after running multiple tests on the pollen researchers found that over 90% of the pollen grains in OFM-3 were fertile.

When crossed between OFM-3 x JG-11 (normal) and OFM-3 x ICCV 96030 (another mutant variety) were performed it was found in the F1 generation of all the crosses that the allele for closed flower was dominant. In the F2 generation the progeny was segregated into a 3:1 ratio, meaning that open flower trait is controlled by 1 allele. This was similar to the open flower trait in ICC 16129. When open flower trait and double flower trait (2 flowers per node/ normal has one) were combined in a dihybrid there was found to be weak linkage between the two traits. But in a dihybrid between open flower and plant type (semi-spreading and spreading of the plant structure) there was a strong connection because none of the progeny in either the F2 or F3 generations were normal plant type with open flower trait.

In crosses between OFM-3, ICC 16129 and ICC 16341 the F1 plants were all normal closed flowers, showing that the open flower trait in all the mutants are controlled by different genes. From this the F2 generations fell into a 9:3:3:1 ratio. When combined with either ICCV 96030 or JG-11, OFM-3 had a higher seed production rate. The highest was at 82.1% when crossed with JG-11. This showed the possibilities of being able to have and open flower trait with a higher percentage of filled pods and it also suggested that the lack of filled pods in an OFM-3 x OFM-3 cross could be due to independently inherited genes that would affect embryo development.

By studying the trait relationships and patterns of inheritance among the different open flower mutant varieties it was found that each mutant variety had a unique gene for the open flower trait. Also, the study of the open flower trait saw opportunities for the hybridization of the chickpea and the creation of breeding lines from the progeny between OFM-3 and normal flowered chickpea.

Hannah Quick