Research Study 2 Sleep-wake disturbances have frequently been reported in bipola

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Research Study 2 Sleep-wake disturbances have frequently been reported in bipolar disorder and schizophrenia, and are considered to be caused by an underlying circadian rhythm disorder. The produces a protein product which is involved in regulating circadian rhythms. The study disorder type I (BD-I) patients in South India. here was designed to investigate the existence of per3 polymorphism in bipolar In exon 18 of the human version of the per3 gene, there is a region that contains a variable number tandem repeat polymorphism (i.e. in the DNA, there is a specific sequence that repeats one after the other for a varying number of times). In humans, the repeat occurs either 4 or 5 times (see following figure, Figure 1). The length of each repeat in the DNA is 54 bp long and therefore each repeat codes for 18 amino acids (see Figure 1) in the Per3 protein. Homo sapiens short allele SSPATTGALSTGSPPRENPSHPTASALSTGSPPHN PSHPTASTLNGLPPSRTPSHPTATVLSTGSPPSES Hono sapiens Figure 1. Alignment of the PER3 VNTR (variable number tandem repeat) region for the two human polymorphisms in the protein sequence. Since the shown in lieu of the repeating sequence is quite long, the amino acid sequence is nucleotide sequence. Each letter represents an amino acid (using the one-letter code for amino tance, M methionine, Peproline, etc.). Each repetition is represented in a different color. (See main page of class website for color version) There is evidence that the per3 polymorphism length is associated with sleep homeostasis. An association has also been found between the onset of bipolar disorder and homozygosity for the five-repeat in per3. Other studies show associations with schizophrenia, or stronger associations based on gender Now that you ve seen the way the two polymorphisms (allele types) differ in length - one has a 4-repeat and one has a 5-repeat - let's look at some of the data that researchers have collected. DNA was isolated and amplified from thirteen individuals that were diagnosed with bipolar disorder or not (controls). The pers repeat region was visualized (results seen in Figure 2 Figure 2. Agarose gel showing per3 alleles for exon 18. These alleles correspond to the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 repeat sequences indicated in Figure 1 Specifically, the 401 bp allele indicates a 5 tandem repeat, while the 347 bp allele indicates a '4" tandem repeat. For instance, 401 bp 4the DNA shown in lane 2 has the genotype of 347 bo (45), as it has one .4. and one .5. repeat present. We can also refer to it by the size of the allele, as indicated on the right side of the gel. Lane 1: DNA ladder; Lanes 2-5: control patients; Lanes 6-13: bipolar disorder patient samples n the DNA results seen above, what does your gut tell you: do you think there is an association between bipolar disorder and a particular per3 allele? Explain your thoughts. A. Give e obvious way to determine if there is an association is to do a two-way table chi-square Set up a two-way table that will allow you to run a chi-square test to see if there is B. Th test. any association between the per3 allele size and bipolar disorder.

Explanation / Answer

Yes, i think there is a clear relation between bipolar disorder and par3 gene as most of the patients that have a bipolar disorder are having only 4 repeats or 300bp band including patient 6,9,10,11,12 and 13. As far as controls are concerned, they are having both 4 repeat region as well as 5 repeat region, so lacking any region in par3 gene seems to be a resulting in bipolar disorder. same is also seen in case of patient 7 that only have 5 repeat region or 400bp region.

Thank you

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