Why are Europeans lactase persistent?
However, most people in Europe and many from other populations continue to produce lactase throughout their life (lactase persistence). In Europe, a single genetic variant, −13,910*T, is strongly associated with lactase persistence and appears to have been favoured by natural selection in the last 10,000 years.
Is lactase persistence an example of convergent evolution?
Once the lactase persistence trait evolved, it quickly spread across northern Europe. A separate independent mutation to the same regulatory DNA region conferred lactase persistence to at least one culture of humans living in Africa (e.g., convergent evolution).
How do you know if you have lactase persistence?
Lactase persistence was determined with hydrogen breath tests. The frequency of lactose malabsorbers was 18.4% in members of Beja tribes over the age of 30, and 73.3% in members of Nilotic tribes over the age of 30.
What type of mutation causes lactase persistence?
Some humans, however, continue to produce lactase throughout adulthood, a trait known as lactase persistence. In European populations, a single mutation (−13910*T) explains the distribution of the phenotype, whereas several mutations are associated with it in Africa and the Middle East.
When did humans become lactose tolerant?
The pattern was the same for all mammals: At the end of infancy, we became lactose-intolerant for life. Two hundred thousand years later, around 10,000 B.C., this began to change. A genetic mutation appeared, somewhere near modern-day Turkey, that jammed the lactase-production gene permanently in the “on” position.
What region of the world has the most lactase persistence?
Global Distribution of Lactase Persistence. Worldwide, only about 35 percent of adults can digest lactose, and most are concentrated in particular geographic regions or “hot spots”: northern Europe, parts of east and west Africa, the Middle East, and South Asia.
How is lactase persistence An example of biocultural evolution?
The Biocultural Coevolution theory proposes that pastoralism and lactase persistence coevolved. This means that they arose around the same time, and both changes were reinforced by the advantages of the other.
What is the difference between lactose tolerance and lactose persistence?
Genetics of Lactase Persistence Lactase persistence, and therefore lactose tolerance, is inherited as a dominant trait. Lactose intolerance is the result of being homozygous for the recessive lactase allele that is poorly expressed after early childhood.
What is lactase persistence can you still drink milk without having any problems?
Lactase persistence is the opposite of lactose intolerance. People who are lactase persistent continue to produce the enzyme lactase beyond infancy and generally throughout life. As a consequence, they are able to digest lactose and drink milk at older ages without adverse effects.
What is the difference between lactose intolerance and lactase persistence?
Lactose intolerance is a recessive trait, whereas lactase persistence is dominant. The lactase persistence locus is between intron 13 and exon 17 of the minichromosome maintenance complex component 6 gene (MCM6) located upstream of the lactase gene (LCT).
What is unique about the mutation in DNA which allows for lactose persistence?
Genetic mutation helps digest lactose A single point mutation in the DNA near to the lactase gene changes the cytosine (C) nucleotide to a thymine (T). Individuals who have the thymine (T) nucleotide are lactose tolerant and can digest milk products in adulthood.
What role do mutations play in the evolution of new traits such as lactase persistence?
What role do mutations play in the evolution of new traits such as lactase persistance? Mutations are always random, these changes can allow new proteins to bind to DNA (regulatory mechanism) or proteins to serve a new function.