What is the drifty gene theory?

What is the drifty gene theory?

Speakman has come up with an alternative theory, nicknamed the ‘drifty gene’ hypothesis. He argues that the modern distribution of obesity stems from a genetic drift in the genes encoding the system that regulates metabolism and controlling an upper limit on our body fatness.

How does the thrifty gene hypothesis explain hunger in humans?

In 1962 Neel [99] put forward the “thrifty gene hypothesis” that states that individuals who could easily store extra energy would have had an evolutionary advantage during famines. Obese and overweight individuals accordingly have this “thrifty gene”. However, this theory has been criticized [100, 101].

How has the thrifty gene contributed to obesity?

The thrifty gene hypothesis suggests that the carriers of the ‘thrifty genes’ survive because they deposit fat between famines. The implication of this is that the primary factor causing famine mortality is running out of energy reserves—that is, starvation, and that fatter people run out of reserves more slowly.

What is thrifty genotype hypothesis?

The basic premise of the thrifty gene hypothesis is that certain populations may have genes that determine increased fat storage, which in times of famine represent a survival advantage, but in a modern environment result in obesity and type 2 diabetes.

Which scenario describes an example of genetic drift?

gene pool. Which scenario describes an example of genetic drift? A drought killed many of the orchids living on a small island. By chance, only the pink and purple varieties survive, whereas the white‑flower variety is lost completely.

How does the thrifty gene hypothesis explain hunger in humans quizlet?

The Thrifty Gene Hypothesis states that humans have survival gene variants that provide protection against a “feast or famine” lifestyle, which cause obesity in societies where it is always feast and never famine.

How do genes effect obesity?

Rarely, obesity occurs in families according to a clear inheritance pattern caused by changes in a single gene. The most commonly implicated gene is MC4R, which encodes the melanocortin 4 receptor. Changes in MC4R that diminish its function are found in a small fraction (<5%) of obese people in various ethnic groups.

Who invented thrifty gene hypothesis?

The thrifty gene hypothesis, formulated by the American geneticist and travelling scientist James V. Neel in 1962, proposed that Indigenous peoples were genetically predisposed to Type 2 diabetes due to the foodways of their ancestors.

What is a real life example of genetic drift?

The bottleneck effect is an extreme example of genetic drift that happens when the size of a population is severely reduced. Events like natural disasters (earthquakes, floods, fires) can decimate a population, killing most individuals and leaving behind a small, random assortment of survivors.

Which of the following scenarios is the best example of the founder effect of genetic drift?

In both cases a small number of individual establish a population and this small “pool” of genes is how genetic diversity is reduced. The wolves are separated from their pack by being released in a new area and then established a new population; this is an example of the founder effect.

What is the thrifty genotype quizlet?

thrifty gene hypothesis. Certain populations have genes that were historically advantageous, enabling efficient storage of fat during times of food abundance- feast- in order to compensate for times of famine. In the modern world- an environment of constant feast- this genotype may lead to obesity and diabetes.

What gene causes weight gain?

MC4R deficiency Subsequently, mutations in MC4R, both in dominant and recessive form, have been demonstrated as the most common cause of inherited early-onset obesity with prevalence between 0.5–6% in different populations.

What is the obesity gene called?

The gene is called FTO, and about 20 percent of white people have a variant of the gene that raises their risk of obesity. The links are clear and widely accepted by scientists.

What is a thrifty metabolism?

In a nutshell, the theory behind “thrifty” metabolism is that when faced with a sudden shortfall of food, some people’s bodies quickly compensate to conserve energy, by burning fewer calories.

Is eye color an example of genetic drift?

The village has now returned to having mostly brown versions of the eye color gene. This is genetic drift – the percentage of blue eye alleles has decreased in the population because of a random event.

Is hunting an example of genetic drift?

Types of Genetic Drift This is usually due to a catastrophic environmental event, hunting a species to near extinction, or habitat destruction. When the size of the population is reduced so quickly, many alleles are lost and the genetic variation of the population decreases.

Which scenario describes an example of founder effect?

Which scenario describes an example of founder effect? Members of a brown-winged species from the mainland fly to an island that is otherwise uninhabited by finches. They establish a new population with different allele frequencies than the original population.

Is there a gene that makes people fat?

Is There a “Fat Gene?” There’s one gene that’s getting a lot of attention, called FTO. Scientists found that people with certain differences in this gene have a 20% to 30% higher chance of obesity.