Horton Teresa H
Department of Neurobiology and Physiology and the Centers for Reproductive Science, Northwestern University, Evanston, Illinois 60208, USA.
Am J Hum Biol. 2005 Jan-Feb;17(1):34-43. doi: 10.1002/ajhb.20092.
The interaction of the genetic program with the environment shapes the development of an individual. Accumulating data from animal models indicate that prenatal and early-postnatal events (collectively called "early-life events") can initiate long-term changes in the expression of the genetic program which persist, or may only become apparent, much later in the individual's life. Researchers working with humans or animal models of human diseases often view the effects of early-life events through the lens of pathology, with a focus on whether the events increase the risk for a particular disease. Alternatively, comparative biologists often view the effects of early-life events through the lens of evolution and adaptation by natural selection; they investigate the processes by which environmental conditions present early in life may prompt the adoption of different developmental pathways leading to alternative life histories. Examples of both approaches are presented in this article. This article reviews the concepts of phenotypic plasticity, natural selection, and evidence from animal models that early-life events can program the activity of the neuroendocrine system, at times altering life history patterns in an adaptive manner. Data from seasonally breeding rodents are used to illustrate the use of maternally derived information to alter the life history of young. In several species, the maternal system transfers photoperiodic information to the young in utero. This maternally derived information alters the response of young to photoperiods encountered later and life, producing seasonally distinct life histories.
基因程序与环境的相互作用塑造了个体的发育过程。来自动物模型的越来越多的数据表明，产前和产后早期事件（统称为“早期生活事件”）可引发基因程序表达的长期变化，这些变化会持续存在，或者可能直到个体生命的后期才会显现出来。研究人类或人类疾病动物模型的研究人员通常从病理学的角度看待早期生活事件的影响，重点关注这些事件是否会增加患特定疾病的风险。另外，比较生物学家通常从进化和自然选择适应的角度看待早期生活事件的影响；他们研究生命早期出现的环境条件可能促使采用不同发育途径从而导致不同生活史的过程。本文给出了这两种方法的实例。本文回顾了表型可塑性、自然选择的概念，以及来自动物模型的证据，即早期生活事件可设定神经内分泌系统的活动，有时以适应性方式改变生活史模式。以季节性繁殖的啮齿动物的数据为例，说明母体传递的信息如何改变幼崽的生活史。在几个物种中，母体系统会在子宫内将光周期信息传递给幼崽。这种母体传递的信息会改变幼崽对日后所遇到光周期的反应，从而产生具有季节性差异的生活史。
