Hedrick P W
Department of Biology, Pennsylvania State University, University Park.
Hum Hered. 1990;40(4):213-20. doi: 10.1159/000153933.
There is substantial evidence that some form of balancing selection is important for loci in the HLA region. Two classic studies found a large deficiency of homozygotes for these loci. Four possible proposed selective explanations were proposed: (1) heterozygous advantage; (2) linked lethal; (3) maternal-fetal interaction, and (4) resistance to infectious disease. These hypotheses as well as another explanation, different male and female gametic frequencies, have been examined here to try and evaluate their potential impact on genotypic frequencies. For any of these selective mechanisms to alone account for the observed homozygous deficiency, selection and/or others factors would have to be extremely strong. The linked lethal selection model and the hypothesis based on different male and female gametic frequencies appear to be unlikely explanations for these observations. Other factors that may influence genotypic frequencies are also discussed.
有大量证据表明，某种形式的平衡选择对HLA区域的基因座很重要。两项经典研究发现这些基因座的纯合子大量缺失。提出了四种可能的选择性解释：（1）杂合优势；（2）连锁致死；（3）母婴相互作用，以及（4）对传染病的抵抗力。这里研究了这些假设以及另一种解释，即不同的雄配子和雌配子频率，以试图评估它们对基因型频率的潜在影响。要使这些选择机制中的任何一种单独解释观察到的纯合子缺失，选择和/或其他因素必须极其强大。连锁致死选择模型和基于不同雄配子和雌配子频率的假设似乎不太可能解释这些观察结果。还讨论了可能影响基因型频率的其他因素。
