Evaluating the genetic and epigenetic contributions to porcine maternal infanticide and their potential use to identify at risk animals

在包括小鼠、大鼠、猪和人在内的几种哺乳动物中观察到了母亲对新生儿的杀婴行为。有相当多的证据表明，这种复杂的异常母体行为具有重要的遗传成分，但也受到相互作用的环境因素的影响。在养猪业中，杀死母体婴儿导致的仔猪损失既有经济影响，也有福利影响。从英国和欧洲的种猪群的规模(分别为400,000头和15,000,000头母猪--DEFRA在2007年估计)保守地估计，英国有20,000-30,000头小猪面临风险，欧洲每胎产下的仔猪有750,000-1,125,000头。因此，利用对猪妈妈杀婴原因的任何了解将是重要的，以减少对养猪业的福利和经济影响。我们一直在研究猪妈妈杀婴，以确定猪的遗传物质中影响妈妈行为的区域。这些遗传学研究已经发现了一些携带基因和DNA序列的染色体片段，这些基因和DNA序列可能对确定这种杀婴行为很重要。调节基因的基因或DNA序列的活性可以通过DNA序列的直接变化(突变)或通过不改变序列但确实改变其活性的DNA修饰来改变；这被称为表观遗传修饰，可以通过相互作用的环境因素来传播和建立。在这个项目中，我们的目标是调查通过我们的遗传学研究确定的候选基因和序列，以寻找DNA序列改变(突变)和DNA修饰(表观遗传学改变)的证据，以提供将这些基因和序列与母亲杀婴行为联系起来的直接证据。这将通过比较受影响的母猪和未受影响的母猪这些候选区域的DNA来完成。在两组动物之间观察到的DNA序列或DNA修饰的差异可能为开发预测性测试提供基础，这些测试可能有助于识别有母亲杀婴行为倾向的母猪。我们将通过在大量动物身上测试受影响的动物和未受影响的动物之间的显著差异来评估这种可能性，在这些动物中，我们有关于它们在出生时和出生后立即的母性行为的良好记录。除了潜在地允许设计预测性测试之外，对猪的母亲杀婴的基因、途径和潜在生物学的更好的理解为开发可能的治疗策略提供了途径。

Maternal infanticide behaviour towards the newborn has been observed in several mammalian species including mouse, rat, pig and human. There is considerable evidence that this complex abnormal maternal behaviour has an important inherited component but is also influenced by interacting environmental factors.In the pig breeding industry, piglet loss as a result of maternal infanticide has both an economic and welfare impact. From the size of the breeding herds in the UK and Europe (400,000 and 15,000,000 sows respectively - DEFRA estimates in 2007) it is conservatively estimated that 20,000-30,000 piglets are at risk in the UK and 750,000-1,125,000 in Europe at each parity. It would, therefore, be important to use any understanding of the causes of porcine maternal infanticide to reduce the welfare and economic impact in the pig breeding industry.We have been studying porcine maternal infanticide in order to identify regions of the pig genetic material that influence maternal behaviour. These genetic studies have uncovered a number of chromosome segments that carry genes and DNA sequences that may be important in determining this infanticide behaviour. The activity of genes or DNA sequences that regulate genes can be altered either by direct changes in the sequence of DNA (mutation) or by a modification of the DNA that does not alter the sequence but does change its activity; this is known as an epigenetic modification and can be both transmissible and established by interacting environmental factors. In this project we aim to investigate the candidate genes and sequences identified by our genetic studies for evidence of DNA sequences change (mutation) and DNA modification (epigenetic change) to provide direct evidence linking these genes and sequences to the maternal infanticide behaviour. This will be done by comparing the DNA in these candidate regions between affected and unaffected sows. The variations in DNA sequence or DNA modification observed between the two groups of animals may provide the basis for developing predictive tests that could be useful in identifying sows predisposed to maternal infanticide behaviour. We will evaluate this possibility by testing significant differences between affected and unaffected animals on a large collection of animals where we have a well documented record of their maternal behaviour at birth and in the immediate postnatal period. In addition to potentially allowing the design of predictive tests, an improved understanding of the genes, pathways and underlying biology of maternal infanticide in pigs offers routes to the development of possible treatment strategies.