Disease at Gandwar
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Disease strikes the dragons
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Trouble has come to Gandwar. In recent years, dragons have begun
to become sick. Usually an extremely rare event indeed, this
sickness has begun to affect dragon populations in several parts
of the island. Healthy dragons have begun to become lethargic. The
disease progresses gradually, causing the dragons' beautiful,
glossy scales scales to turn white and fall off, beginning at the
extremities and then proceeding toward the face. The disease
progresses rapidly and leads to infertility and death. As this
terrible condition known as Scaleblanche has arrived, dragons
across the island have begun to fear for the survival of
populations that have been hearty and hale for eons.
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Disease strikes the dragons
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The dragon populations across the island have decided to hold a council of their elders and geneticists in an attempt to learn enough about the problem to protect themselves from further harm. At the council, they compare stories and experiences and learn some important things:
1. Only the dragons from the Swamp, Valley and Mountain populations are affected by this disease. Desert, Ice and Forest dragons have been strangely unaffected.
2. This disease does not seem to be contagious from one dragon to another.
Because of these clues, the council decrees that a genetic study should be undertaken to attempt learn more about this disease.
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Genetic study
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The dragons have spent much time studying genetics to date, and have stumbled upon small creatures ideal for these studies. Miniature dragon-like creatures known as drakes, populate much of the island. They reproduce easily and live much shorter lifespans than dragons. These qualities make them ideal for breeding and studying. Because the genetics of drakes are quite similar to those of the dragons, they have been studied extensively.
The dragon elders explain that by breeding strains of these drakes, they can perform analyses to determine where on chromosomes genes are located. Your ears perk up – this is precisely what you did to discover where the gene for plates was located! You share your experience with them, hoping it may help.
The elders are indeed very impressed. After hearing about what you have learned at the conference, they hold a vote, and decide that the island dragons will combine their resources. They decree that you should be trained in the process of QTL Analysis. Once you have been trained, they will hire you to perform an analysis to determine where the gene for scaleblanche is located.
Continue to the next section to begin your training.
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QTL Analysis
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This is a plot of a QTL analysis. It was created by breeding two strains of dragons together, one that had a certain trait, and another that didn't, then breeding their children to make many offspring, as you did in a previous section. For example, some of the F2-generation children you made had plates, and others didn't.
Because the children's genes were crossed over at many different points, we can use statistics to determine where the gene for plates is most likely to occur. This graph is similar to the graph that you created, but contains many more points. It shows how likely it is for the gene to occur at a certain place on a chromosome.
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QTL Analysis
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The LOD score is like the match score you saw earlier. It shows the likelihood that an area of the chromosome contains the gene that is causing your targeted phenotype.
The x-axis on the graph has units of centiMorgans, and relates to the relative distance along the chromosome. A chromosome is 100 centiMorgans long.
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Pinpointing a Peak
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QTL Graph
QTL Graph
Continue to the next page after answering.
QTL Graph
The Investigation
Your goal is to find out what is causing this debilitating disease among certain dragons. Remember that you have only Drakes on which to do experiments, and that the various strains of Drakes are matched to various groups of dragons.
Recall that the Mountain, Valley and Swamp dragons are the only strains that are affected with this disease.
Experiments cost money and take time, so you will only be able to perform experiments on a few crosses. Use what you already know about Drakes to help you select which strains to breed in experiments and how many Drakes to use in each experiment. Make sure to keep watch on your budget so you don't run out!
When you find intervals you think you should explore, take notes on what the intervals are. You can explore them with a link on the next page.
Breeding
Select two types of Drakes you would like to breed in an experiment. Click on the button below to
run your experiment. Experimental runs cost $100,000 each, and you start with a budget of $500,000. As you look at scans, make sure to take snapshots and make notes so you don't have to waste your money running any experiments over again. You may wish to zoom in on individual graph results in order to record all information accurately.
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*Affected by Scaleblanche |
Gene Browsing Overview
The image above shows an overview page of the gene browser. This page displays an overview of a specific chromosome opened to a certain interval, and shows the genes as black tick marks. Each gene displayed is named, and clicking on the gene name will display an overview page for that gene, as shown on the next page.
Gene Browsing Overview
This image above shows the gene overview page. This page displays basic information about the selected gene. To show more detail, click on the gene name again. This will show the gene detail, as shown on the next page.
QTL Graph
This page shows detailed information about the gene you selected. Look in the Phenotypic section too see if there is useful information about inherited traits for the gene you are viewing.
Click here now to try out the genome browser
End:
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QTL Analysis
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