Predictive adaptive response

The thrifty phenotype hypothesis is the idea that if an organism suffers from inadequate nutrition in fetal development it will subsequently be predisposed to certain genetic outcomes as an adult. A study done examining glucose tolerance of individuals born during a famine in the Netherlands in 1944-1945 favors the “thrifty phenotype” hypothesis.{{Cite journal|last1=Ravelli|first1=A.|last2=Meulen|first2=J.V.|last3=Michels|first3=R.|last4=Osmond|first4=C.|last5=Barker|first5=D.|last6=Hales|first6=C.|last7=Bleker|first7=O.|date=1998|title=Glucose tolerance in adults after prenatal exposure to famine|journal=The Lancet|volume=351|issue=9097|pages=173–177|doi=10.1016/S0140-6736(97)07244-9|pmid=9449872|s2cid=39879127}} The results of the experiment showed that exposure to famine, particularly in late gestation, led to a decrease in the glucose tolerance of the adults. Other studies on humans have shown cardiovascular and diabetes mortality has been shown to correspond to the nutrition uptake of the parents and grandparents of an offspring during their years before puberty,{{Cite journal|last1=Kaati|first1=G.|last2=Bygren|first2=L.|last3=Edvinsson|first3=S.|date=2002|title=Cardiovascular and diabetes mortality determined by nutrition during parents' and grandparents' slow growth period|journal=European Journal of Human Genetics|volume=10|issue=11|pages=682–688|doi=10.1038/sj.ejhg.5200859|pmid=12404098|doi-access=free}} hypertension in both sexes is the highest in individuals that had been small babies with large placentas,{{Cite journal|last1=Barker|first1=D.J.|last2=Bull|first2=A.R.|last3=Osmond|first3=C.|last4=Simmonds|first4=S.J.|date=1990|title=Fetal and placental size and risk of hypertension in adult life|journal=BMJ|volume=301|issue=6746|pages=259–262|doi=10.1136/bmj.301.6746.259|pmid=2390618|pmc=1663477}} and larger female babies have decreased ovarian suppression compared to smaller babies after intermediate levels of activity in adulthood.{{Cite journal|last1=Jasienska|first1=Grazyna|last2=Thune|first2=Inger|last3=Ellison|first3=P.T.|date=August 22, 2006|title=Fatness at birth predicts adult susceptibility to ovarian suppression: An empirical test of the Predictive Adaptive Response hypothesis|journal=PNAS|volume=103|issue=34|pages=12759–12762|doi=10.1073/pnas.0605488103|pmid=16908839|pmc=1568921|doi-access=free}} All these studies support the thrifty phenotype hypothesis because the prenatal environment determined the phenotype that would be expressed later in life.

Another proposed hypothesis for the presence of PARs is the developmental plasticity hypothesis. A longitudinal study performed in Helsinki, Finland investigated whether catch-up growth of smaller children increased the risk of coronary heart disease later in life.{{Cite journal|last1=Eriksson|first1=J.G.|last2=Forsen|first2=T.|last3=Tuomilehto|first3=J.|last4=Winter|first4=P.D.|last5=Osmond|first5=C.|last6=Barker|first6=D.J.|date=1999|title=Catch-up growth in childhood and death from coronary heart disease: Longitudinal study|journal=BMJ|volume=318|issue=7181|pages=427–431|doi=10.1136/bmj.318.7181.427|pmid=9974455|pmc=27731}} The results of this study coincide with the developmental plasticity hypothesis because as the nutrition of the small participants improved after birth, these undernourished small individuals grew at a quicker rate and had an increased chance of coronary heart disease.  Another study further confirms the longitudinal study performed in Finland by showing that low weight children develop visceral fat during the catch-up growth period which can potentially result in diabetes later in life.{{Cite journal|last1=Ibanez|first1=L|last2=Suarez|first2=L.|last3=Lopez-Bermejo|first3=A.|last4=Diaz|first4=M.|last5=Valls|first5=C.|last6=Zegher|first6=F.D.|date=2008|title=Early Development of Visceral Fat Excess after Spontaneous Catch-Up Growth in Children with Low Birth Weight|journal=The Journal of Clinical Endocrinology & Metabolism|volume=93|issue=3|pages=925–928|doi=10.1210/jc.2007-1618|pmid=18089700|doi-access=free}} Infants that have a low birth weight have been shown to have a reduction in functioning cells, which would instantly have a negative effect on their adult life.{{Cite journal|last1=Widdowson|first1=E.M.|last2=Crabb|first2=D.E.|last3=Milner|first3=R.D.|date=1972|title=Cellular Development of Some Human Organs Before Birth|journal=Archives of Disease in Childhood|volume=47|issue=254|pages=652–655|doi=10.1136/adc.47.254.652|pmid=5046781|pmc=1648291}} Additionally, a study testing drastic changes in childhood body-mass index showed that after two years of age, thin infants who have a comparatively large body-mass index from their birth weight are associated with disorders such as diabetes.{{Cite journal|last1=Bhargava|first1=S.K.|last2=Sachdev|first2=H.S.|last3=Fall|first3=C.H.|last4=Osmond|first4=C.|last5=Lakshmy|first5=R.|last6=Barker|first6=D.J.|last7=Sushant K. Dey|first7=Biswas|last8=Ramji|first8=Siddarth|last9=Reddy|first9=K.S.|date=2004|title=Relation of Serial Changes in Childhood Body-Mass Index to Impaired Glucose Tolerance in Young Adulthood|journal=New England Journal of Medicine|volume=350|issue=9|pages=865–875|doi=10.1056/NEJMoa035698|pmid=14985484|pmc=3408694}} The developmental plasticity hypothesis is apparent in each of these findings because the post birth development determines the health of the individual during adulthood.

Continued research into predictive adaptive responses has the potential to gain crucial insight into the reasons diseases such as diabetes are so widespread.{{Cite journal|last1=Bateson|first1=P.|last2=Barker|first2=D.|last3=Clutton-Brock|first3=T.|last4=Deb|first4=D.|last5=Dudine|first5=B.|last6=Foley|first6=R.A.|last7=Gluckman|first7=P.|last8=Godfrey|first8=K.|last9=Sultan|first9=S.E.|date=2004|title=Developmental plasticity and human health|journal=Nature|volume=430|issue=6998|pages=419–421|doi=10.1038/nature02725|pmid=15269759|bibcode=2004Natur.430..419B|s2cid=4374045}}

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Category:Evolutionary biology terminology