Thrifty phenotype
Encyclopedia
The thrifty phenotype hypothesis says that reduced fetal growth is strongly associated with a number of chronic conditions later in life. This increased susceptibility results from adaptations made by the fetus in an environment limited in its supply of nutrients. These chronic conditions include coronary heart disease
, stroke
, diabetes, and hypertension
.
Proponents of this idea say that in poor nutritional conditions, a pregnant woman can modify the development of her unborn child such that it will be prepared for survival in an environment in which resources are likely to be short, resulting in a thrifty phenotype
(Hales & Barker, 1992). It is sometimes called Barker's hypothesis, after David J. P. Barker, a researcher at the University of Southampton
who published the theory in 1997.
Many human diseases in adulthood are related to growth patterns during early life, determining early-life nutrition as the underlying mechanism. The thrifty phenotype hypothesis suggests that early-life metabolic adaptations help in survival of the organism by selecting an appropriate trajectory of growth in response to environmental cues. Recently, some scientists have proposed that the thrifty phenotype prepares the organism for its likely adult environment in long term. However, environmental changes during early development may result in the selected trajectory becoming inappropriate, resulting in adverse effects on health. This paradox generates doubts about whether the thrifty phenotype is adaptive for human offspring. Thus, the thrifty phenotype should be considered as the capacity of all offspring to respond to environmental cues during early ontogenetic development. It has been suggested that the thrifty phenotype is the consequence of three unlike adaptive processes: maternal effects, niche construction and developmental plasticity, which all are influenced by the brain. While developmental plasticity demonstrates an adaptation by the offspring, niche
construction and parental effects are result of parental selections rather than offspring fitness. Therefore, the thrifty phenotype can be described as a manipulation of offspring phenotype for the benefit of maternal fitness. The information that enters offspring
phenotype during early development mirror the mother’s own developmental experience and the quality of the environment during her own maturation rather than predicting the possible future environment of the offspring
Individuals with a thrifty phenotype will have "a smaller body size, a lowered metabolic rate and a reduced level of behavioural activity… adaptations to an environment that is chronically short of food" (Bateson & Martin, 1999). Those with a thrifty phenotype who actually develop in an affluent environment may be more prone to metabolic disorders, such as obesity and type II diabetes, whereas those who have received a positive maternal forecast will be adapted to good conditions and therefore better able to cope with rich diets. This idea (Barker, 1992) is now widely (if not universally) accepted and is a source of concern for societies undergoing a transition from sparse to better nutrition (Robinson, 2001).
The study of both the thrifty gene hypothesis and the thrifty phenotype hypothesis has led to a new line of thinking that takes into account the failures and paradigms of the two hypotheses. The thrifty epigenotype hypothesis claims the following:
Coronary heart disease
Coronary artery disease is the end result of the accumulation of atheromatous plaques within the walls of the coronary arteries that supply the myocardium with oxygen and nutrients. It is sometimes also called coronary heart disease...
, stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
, diabetes, and hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
.
Proponents of this idea say that in poor nutritional conditions, a pregnant woman can modify the development of her unborn child such that it will be prepared for survival in an environment in which resources are likely to be short, resulting in a thrifty phenotype
Phenotype
A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...
(Hales & Barker, 1992). It is sometimes called Barker's hypothesis, after David J. P. Barker, a researcher at the University of Southampton
University of Southampton
The University of Southampton is a British public university located in the city of Southampton, England, a member of the Russell Group. The origins of the university can be dated back to the founding of the Hartley Institution in 1862 by Henry Robertson Hartley. In 1902, the Institution developed...
who published the theory in 1997.
Many human diseases in adulthood are related to growth patterns during early life, determining early-life nutrition as the underlying mechanism. The thrifty phenotype hypothesis suggests that early-life metabolic adaptations help in survival of the organism by selecting an appropriate trajectory of growth in response to environmental cues. Recently, some scientists have proposed that the thrifty phenotype prepares the organism for its likely adult environment in long term. However, environmental changes during early development may result in the selected trajectory becoming inappropriate, resulting in adverse effects on health. This paradox generates doubts about whether the thrifty phenotype is adaptive for human offspring. Thus, the thrifty phenotype should be considered as the capacity of all offspring to respond to environmental cues during early ontogenetic development. It has been suggested that the thrifty phenotype is the consequence of three unlike adaptive processes: maternal effects, niche construction and developmental plasticity, which all are influenced by the brain. While developmental plasticity demonstrates an adaptation by the offspring, niche
Niche cell
Niché cells are specific anatomic locations that regulate how stem-cell populations participate in tissue generation, maintenance and repair. The niché performs several functions:...
construction and parental effects are result of parental selections rather than offspring fitness. Therefore, the thrifty phenotype can be described as a manipulation of offspring phenotype for the benefit of maternal fitness. The information that enters offspring
Offspring
In biology, offspring is the product of reproduction, of a new organism produced by one or more parents.Collective offspring may be known as a brood or progeny in a more general way...
phenotype during early development mirror the mother’s own developmental experience and the quality of the environment during her own maturation rather than predicting the possible future environment of the offspring
Individuals with a thrifty phenotype will have "a smaller body size, a lowered metabolic rate and a reduced level of behavioural activity… adaptations to an environment that is chronically short of food" (Bateson & Martin, 1999). Those with a thrifty phenotype who actually develop in an affluent environment may be more prone to metabolic disorders, such as obesity and type II diabetes, whereas those who have received a positive maternal forecast will be adapted to good conditions and therefore better able to cope with rich diets. This idea (Barker, 1992) is now widely (if not universally) accepted and is a source of concern for societies undergoing a transition from sparse to better nutrition (Robinson, 2001).
The study of both the thrifty gene hypothesis and the thrifty phenotype hypothesis has led to a new line of thinking that takes into account the failures and paradigms of the two hypotheses. The thrifty epigenotype hypothesis claims the following:
- The ability to conserve, acquire and expend energy is an innate, ancient trait that we all possess.
- These traits imbedded in the genome are quite protected against mutations.
- Disease susceptibility (as in Type II diabetes) is predominantly determined by epigenetic variations.
- These changes can be inherited across generations.
- Leptin has been identified as a possible gene for the acquisition of these thrifty traits (Stöger, 2008).
See also
- Evolutionary developmental psychologyEvolutionary developmental psychologyEvolutionary developmental psychology, , is the application of the basic principles of Darwinian evolution, particularly natural selection, to explain contemporary human development...
- Evolutionary physiologyEvolutionary physiologyEvolutionary physiology is the study of physiological evolution, which is to say, the manner in which the functional characteristics of individuals in a population of organisms have responded to selection across multiple generations during the history of the population.It is a subdiscipline of both...
- Phenotypic plasticityPhenotypic plasticityPhenotypic plasticity is the ability of an organism to change its phenotype in response to changes in the environment. Such plasticity in some cases expresses as several highly morphologically distinct results; in other cases, a continuous norm of reaction describes the functional interrelationship...
- Trivers–Willard hypothesis
- Thrifty gene hypothesisThrifty gene hypothesisThe thrifty gene hypothesis was proposed by geneticist James V. Neel in 1962 to resolve a fundamental problem. Diabetes is clearly a very harmful medical condition. Yet it is quite common, and it was already evident to Neel that it likely had a strong genetic basis...
- Prenatal nutrition and birth weightPrenatal nutrition and birth weightNutrition and weight management before and during pregnancy has a profound effect on the development of infants. This is a rather critical time for healthy fetal development as infants rely heavily on maternal stores and nutrient for optimal growth and health outcome later in life. Prenatal...