Friend Angela, DeFries John C, Wadsworth Sally J, Olson Richard K
Department of Psychology, 345 UCB, University of Colorado at Boulder, Boulder, CO 80309, USA.
Behav Genet. 2007 May;37(3):477-86. doi: 10.1007/s10519-007-9145-4. Epub 2007 Mar 8.
Previous twin studies have suggested a possible developmental dissociation between genetic influences on word recognition and spelling deficits, wherein genetic influence declined across age for word recognition, and increased for spelling recognition. The present study included two measures of word recognition (timed, untimed) and two measures of spelling (recognition, production) in younger and older twins. The heritability estimates for the two word recognition measures were .65 (timed) and .64 (untimed) in the younger group and .65 and .58 respectively in the older group. For spelling, the corresponding estimates were .57 (recognition) and .51 (production) in the younger group and .65 and .67 in the older group. Although these age group differences were not significant, the pattern of decline in heritability across age for reading and increase for spelling conformed to that predicted by the developmental dissociation hypothesis. However, the tests for an interaction between genetic influences on word recognition and spelling deficits as a function of age were not significant.
以往的双胞胎研究表明，基因对单词识别和拼写缺陷的影响可能存在发育上的分离，即基因对单词识别的影响随年龄增长而下降，而对拼写识别的影响则随年龄增长而增加。本研究对年轻和年长的双胞胎进行了两项单词识别测试（限时、不限时）和两项拼写测试（识别、书写）。年轻组中两项单词识别测试的遗传度估计值分别为0.65（限时）和0.64（不限时），年长组中分别为0.65和0.58。对于拼写，年轻组的相应估计值分别为0.57（识别）和0.51（书写），年长组中分别为0.65和0.67。虽然这些年龄组差异不显著，但阅读遗传度随年龄下降而拼写遗传度随年龄增加的模式符合发育分离假说的预测。然而，基因对单词识别和拼写缺陷的影响随年龄变化的交互作用检验并不显著。
