Are extended twin family designs worth the trouble? A comparison of the bias, precision, and accuracy of parameters estimated in four twin family models.
Are extended twin family designs worth the trouble? A comparison of the bias, precision, and accuracy of parameters estimated in four twin family models.
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DOI：
10.1007/s10519-009-9320-x
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发表时间：
2010-05
影响因子：
2.6
通讯作者：
Duncan LE
中科院分区：
文献类型：
--
作者：
Keller MC;Medland SE;Duncan LE
经典双胞胎设计 (CTD) 使用从同卵双胞胎和异卵双胞胎中观察到的协方差来推断表型变异的遗传和环境原因的相对大小。尽管它被广泛使用，但众所周知，如果不满足其严格的假设，CTD 可能会产生有偏差的估计。通过对观察到的双胞胎亲属以及双胞胎本身的协方差进行建模，大双胞胎家庭设计 (ETFD) 需要不太严格的假设，可以估计更多的感兴趣参数，并且应该产生比 CTD 更少偏差的估计。然而，ETFD 的使用和解释更加复杂，并且通过尝试估计大量参数，参数估计的精度可能会受到影响。本文是对一个简单问题的正式调查：是否值得在行为遗传学中使用更复杂的模型（例如 ETFD）？特别是，我们比较了 CTD 和三个日益复杂的 ETFD 估计值的偏差、精度和准确度。我们发现 CTD 在估计广义遗传力方面做得不错，但 CTD 对共同环境影响以及加性与非加性遗传方差的相对重要性的估计可能存在偏差，有时甚至非常严重。另一方面，日益复杂的 ETFD 比更简单的模型更准确，对假设的敏感度也更低。我们的结论是，对表征环境或遗传变异组成感兴趣的研究人员应尽可能使用 ETFD。
The classical twin design (CTD) uses observed covariances from monozygotic and dizygotic twin pairs to infer the relative magnitudes of genetic and environmental causes of phenotypic variation. Despite its wide use, it is well known that the CTD can produce biased estimates if its stringent assumptions are not met. By modeling observed covariances of twins’ relatives in addition to twins themselves, extended twin family designs (ETFDs) require less stringent assumptions, can estimate many more parameters of interest, and should produce less biased estimates than the CTD. However, ETFDs are more complicated to use and interpret, and by attempting to estimate a large number of parameters, the precision of parameter estimates may suffer. This paper is a formal investigation into a simple question: Is it worthwhile to use more complex models such as ETFDs in behavioral genetics? In particular, we compare the bias, precision, and accuracy of estimates from the CTD and three increasingly complex ETFDs. We find the CTD does a decent job of estimating broad sense heritability, but CTD estimates of shared environmental effects and the relative importance of additive versus non-additive genetic variance can be biased, sometimes wildly so. Increasingly complex ETFDs, on the other hand, are more accurate and less sensitive to assumptions than simpler models. We conclude that researchers interested in characterizing the environment or the makeup of genetic variation should use ETFDs when possible.
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影响因子：
2.6
作者：
Carey, G
通讯作者：
Carey, G
影响因子：
0.9
作者：
Medland, Sarah E.;Keller, Matthew C.
通讯作者：
Keller, Matthew C.
影响因子：
2.6
作者：
Reynolds, CA;Baker, LA;Pedersen, NL
通讯作者：
Pedersen, NL
影响因子：
3.8
作者：
CRNOKRAK, P;ROFF, DA
通讯作者：
ROFF, DA
DOI：
10.1375/twin.12.1.26
发表时间：
2009-02
期刊：
Twin research and human genetics : the official journal of the International Society for Twin Studies
影响因子：
--
作者：
Maes HH;Neale MC;Medland SE;Keller MC;Martin NG;Heath AC;Eaves LJ
通讯作者：
Eaves LJ