Evolution of lactase gene in homo sapiens - Term Paper Example

Genetics and molecular studies of genes presently and in the past are pointing towards an evolutionary cause behind its persistence in adults. In order to prove that something is a product of evolution, one must demonstrate that a favourable trait mutated. Additionally, one must show that the trait was transmittable to offspring and the environment favoured that trait. This may necessitate genital analysis of pre-historical data as well as present ones. Furthermore, these patterns ought to be analysed in relation to the behavioural or cultural patterns of the subjects as it could affect the adoption of the trait.

The paper will look into these dimensions in order to illustrate the evolution of the lactase gene. Advantages and disadvantages in a population Lactase-phlorizin hydrolase (LPH) is the enzyme responsible for the digestion of lactose in Homo sapiens. Lactase activity in the intestines depends on the maturity of the person under consideration. Infants between two to eleven months old have some of the highest activity levels. As a child reaches the age of five, lactase activity reduces, and this may continue in subsequent times.

Therefore, the amount of the LPH enzyme will reduce because a person stops suckling or consuming lactose. Conversely, some adult populations continue to maintain high level of lactase activity, especially those with North European descent. This persistence of activity is an evolutionary development that coincides with the development of the dairy industry in most parts of the world (Grand et. al. 618). It is thus advantageous to ingest lactose in adulthood because this will not limit the person’s dietary intake.

They will have the freedom to consume milk without dealing with health challenges. Prior to the domestication of animals, adult populations did not need the lactase enzyme. Therefore non persistence was the available state. However, this dramatically changed when animals started providing milk to the human population. It became genetically advantageous to retain the lactase enzyme in adulthood. Since only persons with this enzyme can enjoy the nutritional benefits of milk, then lactase persistence is beneficial.

Culture dictated gene adaptability and advanced evolution (Hollox 267). Milk is nutritionally beneficial to the human body because it a rich source of calcium. Therefore, consumption of the beverage would protect one from bone-related diseases such as osteoporosis (Swallow 208). Rickets is an undesirable condition that also emanates from the lack of calcium. It is a selective force that favoured the ingestion of milk. The lack of the lactase enzyme in adults leads to a number of difficulties when dealing with the digestion of milk.

Once such individuals consume milk, the lactose in milk will stay undigested. No alteration in blood glucose will be detected if a test is done. Instead, the product will enter the colon and be fermented. Fermentation causes the production of gases such as hydrogen and fatty acids. This is possible through the action of bacteria in the gut. Usually, persons who are lactose intolerant will suffer from bloating or gaseousness, diarrhoea, nausea, cramps and discomfort after taking milk. The gases that are produced after fermentation can be detected through portable hydrogen analysers (Itan et. al. 8).

Therefore, it is highly desirable to be lactase persistent. All the complications that emanate from fermentation would be absent. Swallow (207) highlights some potential risks of having