Depression: Pioneering study pinpoints 44 genetic culprits

         From a new study it was found that the genetic data of thousands of participants identified 44 genetic loci linked with the risk of depression. Depression is one of the most common mental disorders in the U.S. Some risk factors of depression are the combinations of biological, environmental, and of a psychological nature. Inherited genetic variations are apart of the biological factors, however before this study researchers have had a hard time pinpointing which genetic locations in our DNA are directly linked with having a higher risk of depression. 

       The researchers managed to access and analyze seven different sets of genetic data, as well as identified 44 genetic loci that are linked with the risk of depression. Of these 44, 30 of them were not known before to be risk factors. The study resulted in them discovering that there are 153 genes linked with depression. This could lead to the improvement of  treatments for this condition.
        In my opinion these results are very important and could have large impact on future studies. Being in college there are many students that get over whelmed with school work and end up becoming depressed. It affects many people all around us. The results of this study can lead to further studies for developing better treatments that target genetic factors involved in depression. This can be the beginning of finding a way to prevent major depression. 

Link to article:
https://www.medicalnewstoday.com/articles/321652.php
Link to more information:
https://www.medicalnewstoday.com/kc/depression-causes-symptoms-treatments-8933

Genetics and Obesity:

Obesity has been a very common point for the United States for decades. The United States obesity rate is far too high, and a large amount of that is contributed to genetics. There are several diseases regarding obesity, a few examples are Prader–Willi syndrome, Albright hereditary osteodystrophy,  and ulnar-mammary syndrome, all three are autosomal dominant disorders. There are many loci in which each disorder is present.While there is widespread acceptance that hereditary factors might predispose to human obesity, it is frequently assumed that such factors would influence metabolic rate or the selective partitioning of excess calories into fat. However, it is notable that, thus far, all monogenic defects causing human obesity actually disrupt hypothalamic pathways and have a profound effect on satiety and food intake. Along with the genetic  predisposition to obesity, many individuals also have environmental predispose to obesity, which only compounds the patients problem making them eat more and more. 

Susceptibility to Asthma:

Asthma is a chronic respiratory condition that inflames and narrows the airways making it difficult to breath; some individuals can be more susceptible than others. A large factor in increased suspibility is bronchial hyperresponsiveness, which is a heightened bronchoconstrictor response to a variety of stimuli. Bronchial hyper responsiveness is related to serum IgE levels and airway inflammation. The experiment done compared 303 children and grandchildren of 84 probands with asthma selected from a homogeneous population in the Netherlands and each participant's Ventilatory function, bronchial responsiveness to histamine, and serum total IgE were measured. The results showed that 

"a trait for an elevated level of serum total IgE is coinherited with a trait for bronchial hyperesponsiveness and that a gene governing bronchial hyperresponsiveness is located near a major locus that regulates serum IgE levels on chromosome 5q. These findings are consistent with the existence of one or more genes on chromosome 5q31-q33 causing susceptibility to asthma."

This study shows a correlation with asthma and serum IgE and that if an individual has high IgE levels, they have a high level of bronchial hyper responsiveness and in turn have asthma.

How genes influence marijuana use

             

                 Members who smoked marijuana more than five times were studied. From this study, it was found that the use of marijuana is influenced by genetic factors. Marijuana has different effects such as anxiety, depression, confusion, delusions and euphoria. However, people have different reactions to marijuana. These different reactions depend on situational differences and chemical changes in the body. There is proof from animal research that a Drug reaction is influenced by genetics. For example, different kinds of genes control responses of motor stimulation. A research study has found that interaction among a small number of genetic loci or a single gene of major affect produces non-addictive genetic influences. The two factors of negative effects or pleasant effects are both influenced by genes and the environment. One of the genetically influenced factors that mediate the association between genotype and phenotype of this drug using behavior is because of genetic influence on subjective effects. In conclusion, for marijuana, the majority of genetic factors that contribute to the use of the drug also contribute to dependence symptoms. 

Link 1: http://www.dartmouth.edu/~dcare/pdfs/fp/GreenAlan-HowDoGenesInfluenceMarijuanaUse.pdf 

Related link: http://onlinelibrary.wiley.com/doi/10.1111/j.1360-0443.1997.tb03372.x/abstract

Novel Genetic Loci Identified for High-Frequency Hearing Loss

As people get older, they gradually lose the ability to hear high-pitched sounds. This occurrence is called presbycusis. The genetic loci have been recently found that affects a human’s ability to hear high pitched sounds. These genetic loci affect certain portions of the hearing frequency map and especially the loss of hearing as age increases. The National Institute of Deafness and other Communication Disorders (NIDCD) successfully identified two loci that affected hearing at high frequencies. These two loci are Hfhl1 and Hfhl3. To discover these two loci the NIDCD used genome-wide linkage analysis. The Hfhl1 loci is thought to be confined to hearing frequencies from 25-44 kHz of the tonotopic map. The Hfhl3 loci is thought to be confined to the 35-44 kHz region on the tonotopic map inside the inner ear. The loss of high-pitched sounds is a result of variations in gene activity and cochlear partition. There is different hearing sensitivity located in different sections of the cochlea of the inner ear. The loci Hfhl1 and Hfhl3 account for only a portion of the variation in high-pitched hearing loss. Additional genotyping and analysis needs to be done in order to find the remaining loci that affect high-pitched frequency loss.