Major depression (MD) is one of the major mood disorders (MMD). Typically, those affected by MD exhibit persistent low mood and reduced levels of enjoyment. There have been studies involving twins and families (with biologically related and adopted children) that suggest both genetic and environmental factors play a role in the development of MD (Levinson, 2006). A factor that plays a prominent role in development of MD is the dysfunction of circadian rhythm (Srinivasan et al. 2006). Those affected exhibit disturbances in their sleep/wake cycle, diurnal mood variations, and cyclical recurrence of depressive symptoms.
Figure 1-Diagrams for primer design. (a) Diagram of G>T / G>A SNP amplification. (b) Diagram of C>G SNP amplification. (c) General diagram of exon region amplification.
Figure 2-Identification of G>C transversion in region containing SNP rs4328989. (a) Diagram of AANAT gene structure with C>G SNP (b) Gel image of PCR products for each DNA sample and non-template control (NTC). (c-e) DNA sequences of PCR products. Chromatograms for forward product (top) and reverse product (bottom).
Figure 3-Identification of G>T transversion in region containing SNP rs3760138. (a) Diagram of AANAT gene structure with G>T / G>A SNP (b) Gel image of PCR products for each human DNA sample and non-template control (NTC). (c-e) DNA sequences of PCR products. Chromatogram for forward product (top) and reverse product (bottom).
Figure 4-Amplification of exonic regions 2-6 of AANAT gene. (a-e) Gel image of PCR products for each human DNA sample and non-template control (NTC) (Left) Sequence alignment for amplified product sequence flanking each exon region with actual exon sequence from NCBI website (Right). (f) Identification of C>T transition in exon 5 region of AANAT. Chromatogram for forward product (top) and reverse product (bottom)
Disruptions in circadian rhythm are often associated with development of major depression (MD). Aralkylamine N-acetyltransferase (AANAT) is a regulatory enzyme responsible for the synthesis of melatonin, the regulatory hormone of circadian rhythm. Two single nucleotide polymorphisms (SNPs) (rs3760138 and rs4238989) in the AANAT gene are commonly associated with MD development. rs3760138 is a G>T / G>A variant while rs4238989 is a C>G variant. Primers were developed to amplify the regions of AANAT that contain these genetic variations. Using de-identified human DNA samples, the SNP-containing regions were amplified and sequenced to determine whether the samples contained the SNPs. The potential SNP regions were successfully amplified and sequenced in this proof-of-principle study, supporting the use of this method for screening for SNPs associated with MD.
I would like to thank Anthony Evans for all of his guidance and generous donation of DNA samples. I would also like to thank Devin Rocks for all of his support during my project. Finally, I would like to thank Dr. Berish Rubin for his help and support to make this project possible.
|This document was last modified 05/19/2019.|
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