Bishop D V M, Adams C V, Norbury C F
Department of Experimental Psychology, University of Oxford, UK.
Genes Brain Behav. 2006 Mar;5(2):158-69. doi: 10.1111/j.1601-183X.2005.00148.x.
Children with language impairments have limitations of phonological short-term memory (STM) and have distinctive problems with certain aspects of grammar. Both deficits have been proposed as phenotypic markers of heritable language impairment. We studied 173 twin pairs, selected to be over-representative of children with risk of developmental language impairment, using a battery of standardized language and intelligence tests, a test of nonword repetition to index phonological STM and two elicitation tasks to assess use of verb tense marking. As predicted, the phonological STM and the verb tense measures both discriminated children with risk of language impairment from low risk children, and DeFries-Fulker analysis showed that impairments on both tasks were significantly heritable. However, there was minimal phenotypic and etiological overlap between the two deficits, suggesting that different genes are implicated in causing these two kinds of language difficulty. From an evolutionary perspective, these data are consistent with the view that language is a complex function that depends on multiple underlying skills with distinct genetic origins.
有语言障碍的儿童存在语音短期记忆（STM）缺陷，并且在语法的某些方面存在独特问题。这两种缺陷都被认为是遗传性语言障碍的表型标记。我们研究了173对双胞胎，这些双胞胎被挑选出来以过度代表有发展性语言障碍风险的儿童，使用了一系列标准化语言和智力测试、一项用于评估语音STM的非词重复测试以及两项用于评估动词时态标记使用情况的引出任务。正如所预测的那样，语音STM和动词时态测量都能区分有语言障碍风险的儿童和低风险儿童，并且德弗里斯-富尔克分析表明，两项任务上的障碍都具有显著的遗传性。然而，这两种缺陷之间的表型和病因重叠极小，这表明不同的基因与导致这两种语言困难有关。从进化的角度来看，这些数据与语言是一种复杂功能的观点一致，这种功能依赖于具有不同遗传起源的多种潜在技能。
