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x-inactivation in tortoiseshell cats

Postby KLS7 » Wed Aug 14, 2019 2:19 pm

I am doing the science project on x-inactivation in tortoiseshell cats to determine if the display of black/brown vs orange/red is random or pre-determined. Female cats have two x chromosomes of the orange coloring allele and only one can be active at a time. If the O out of the Oo is active, the area will have orange/red fur, and if the o out of Oo is active, it will be black/brown.

I think my independent variable is the pictures of 15 female tortoiseshell cat faces divided into 12 areas while the dependent variable is charting if the pattern is random or pre-determined among the pictures.

As I do not need to control the environment in this experiment, like temperature, light, etc., what would be a control, (ex. 12 week or older female cats)? Also, would constants be that all the cats are female tortoiseshell cats with no other color fur, same camera angle, etc. ? I am a bit confused on that as my experiment is different than ones I have done before.

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Re: x-inactivation in tortoiseshell cats

Postby EmmaGriffiths » Thu Aug 15, 2019 9:13 am

Hey there!

This is actually a really interesting experiment; I love studying genetics, and I had no clue that inactivation occurred in female cats. Very cool!

Your independent and dependent variables sound like a good start to a procedure for the experiment, though I'm not sure that "variable" is the proper name for these steps. I believe the independent variable would be x-inactivation while the dependent variable would be fur pattern (because the activated allele determines the fur color, right?).

Controls and constants generally mean the same thing: variables that do not change throughout your experiment. That being said, I agree that camera angle, age, and species are all perfect constants. Other constants could be time period (when the cat was alive), genotypes of the parents, size of the cat, etc. The point is that you want the cats to be as similar as possible (disregarding the fur, which is part of the dependent variable). However, I know it may not be possible to get these specific details, so the constants you have listed would be perfect even alone.

I hope this helped -- please don't be scared to ask if you have any other questions or if you need any clarification on this information. Good luck and have fun :)


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