Spencer H G
Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
Annu Rev Genet. 2000;34:457-477. doi: 10.1146/annurev.genet.34.1.457.
At a small number of mammalian loci, only one of the two copies of a gene is expressed. Just which copy is expressed depends on the sex of the parent from which that copy was inherited. Such genes are said to be imprinted. The functional haploidy implied by imprinting has a number of population genetic consequences. Moreover, since diploidy is widely believed to be advantageous, the evolution of this non-Mendelian form of expression requires an explanation. Here I examine some of the theoretical and mathematical models investigating these two aspects of imprinting. For instance, the dynamics and equilibrium properties of many models of natural selection at imprinted loci are formally equivalent to models without imprinting. And different approaches to modeling the problem of the evolution of imprinting reveal the weakness of several of the apparent predictions of various verbal hypotheses about why imprinting has evolved.
在少数哺乳动物基因座中，基因的两个拷贝中只有一个会表达。究竟哪个拷贝会表达取决于该拷贝所继承的亲本的性别。这样的基因被称为印记基因。印记所隐含的功能性单倍体具有许多群体遗传学后果。此外，由于普遍认为二倍体是有利的，这种非孟德尔式表达形式的进化需要一个解释。在这里，我研究了一些探讨印记这两个方面的理论和数学模型。例如，许多印记基因座自然选择模型的动力学和平衡特性在形式上等同于无印记的模型。并且，对印记进化问题进行建模的不同方法揭示了关于印记进化原因的各种口头假设的一些明显预测的弱点。
