Obesity, Genotype, and Phenotype
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Obesity, Genotype, and Phenotype
Obesity is an intricate heterogeneous illness or medical condition controlled by the genes and environmental settings and their relations. Obesity occurs when excess body fats accumulate to the extent of developing severe effects on human health. Typically, obesity is calculated using the BMI (Body Mass Index) and supplementary evaluations based on the distribution of fat by observing both total cardiovascular risk factors and the waist-hip ratio. Notably, genetic factors make up about 40% to 90% of human variations on body mass index. Genetics is fundamental “the study of genes” while aiming to explain genes and their functionality. This research examines the relationship between obesity and genetics or genotypes and phenotypes.
The chemistry between genetics and obesity
For a clear understanding of the connection between obesity and genetics, it is essential to understand that a gene is the “primary physical and functional heredity unit” and that genes comprise of DNAs (Deoxyribonucleic acid). Studies have established variants in different genes that might influence weight gains as well as the distribution of body fats, only in a few situations where genes are the central cause of obesity.
Genetics contribution to obesity
Recent studies by the Obesity Medical Association discover more than 50 genes that are highly linked to obesity. These studies thus reveal that genetics contribute between 40% and 70% of all obesity cases (Obesity Medicine Association, 2020). Although environmental changes have considerably influenced the rise in obesity rates in the past two decades, the absence or presence of genetic factors predisposes or protect individuals from obesity.
A Predisposition of obesity Genetics
Often, people who develop obesity have a range of genes that predispose them towards gaining excess weights. The “Fat mass and obesity-associated (FTO)” gene is one of these genes that highly predispose individuals to obesity (Farooqi & O’Rahilly, 2006). About 43% of the people have the FTO gene. Because of the readily available foods, individuals with the “fat mass and obesity-associated gene” are highly likely to develop challenges on restricting their desire to consume calories. Notably, the presence of the latter gene, among other genes, can cause a range of behaviors that can lead to obesity. Some of these experiences include increased levels of hunger and caloric intake, increased predisposition to be sedentary as well as store body fats. Other skills include limited controls on overeating and satiety.
Genes causing obesity
The obesity-associated noncoding area of the Fat mass and obesity-associated gene directly interacts with the promoter of Iroquois homeobox genes IRX3 and IRX5, and the FTO in humans. Besides, MC4R is the most familiar implicated gene that encodes the Melanocortin 4 Receptor (MC4R). Notably, variations in the MC4R that weaken its functionality are present in less than 5% of the obese population among various ethnic communities (Farooqi & O’Rahilly, 2006). However, affected individuals, mainly the children, develop extreme experiences of hunger and hence become obese because of hyperphagia or consistent overeating behavior. Polymorphisms in diverse metabolism and appetite-controlling genes predispose to obesity in particular dietary conditions. Of importance, the percentage of genetically influenced obesity varies widely depending on the range of people evaluated. Therefore, the rate can range from 6% to 85%. According to other studies, about 118 candidate genes are linked to obesity. Examples of these genes are genes encoding leptin (LEP), Insulin receptor (INSR), uncoupling proteins (UCP), and leptin receptor gene.
Phenotypes and genotypes for obesity
BMI, hip circumference, and waist circumference are some of the most apparent phenotypes of obesity. A recent study established that minor allele of UCP2 Ins45bp is highly associated with the entire peripheral and abdominal obesity while under a recessive transmission mode. Additionally, the study confirms that the allele of SHP depicts increased hip circumference while a decrease in waist in some IAA and BMI is observed in MCHR1. In light of this, genetic factors account for various predispositions to obesity among persons.
Conclusion
The above discussion establishes that while environmental factors are significant causes of obesity, genetics plays a vital role in obesity development. The study confirms that the “Fat mass and obesity-associated (FTO)” gene is one of the genes that highly predispose individuals to obesity. Body mass index, hip, and waist circumference are some of the phenotypes associated with obesity.
References
Obesity Medicine Association (2020). Obesity and Genetics: Nature and Nurture. Retrieved from https://obesitymedicine.org/obesity-and-genetics/
Farooqi, I. S., & O’Rahilly, S. (2006). Genetics of obesity in humans. Endocrine Reviews, 27(7), 710-718.