Position of a 'green-red' hybrid gene in the visual pigment array determines colour-vision phenotype
Position of a 'green-red' hybrid gene in the visual pigment array determines colour-vision phenotype
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DOI：
10.1038/8798
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发表时间：
1999-05-01
期刊：
影响因子：
30.8
通讯作者：
Deeb, SS
中科院分区：
文献类型：
--
作者：
Hayashi, T;Motulsky, AG;Deeb, SS
x连锁的红色和绿色色素基因排列成首尾串联阵列（1-3）。色觉异常的色觉缺陷（在5%的欧洲血统男性中）与5‘-绿-红-3’视觉色素杂交基因有关（4,5），这种基因也可能存在于色觉正常的男性中（5-7）。为了解释为什么具有正常红色、正常绿色和绿-红杂交基因的男性可能具有正常或多变性的色觉，我们假设只有前两个基因表达（8,9），而只有当绿-红杂交基因占据第二个位置并优先于占据更远位置的正常绿色色素基因表达时才会出现deuteranomaly。本研究采用远程PCR扩增技术，对10只携带3种视觉色素基因（红色、绿色和绿红杂交）的雄性雄性（8只雌雄同体，2只雌雄同体）进行了研究，探讨杂交基因在阵列中的位置是否决定了基因的表达。绿-红杂交基因总是在第二个位置，而第一个位置总是被红色基因占据)。相反，在两名拥有红、绿、绿-红杂交基因和正常色觉的男性中，杂交基因占据了第三个位置。对红、绿、绿-红三种基因型男性死后视网膜色素基因mRNA表达进行分析发现，绿-红杂交基因仅在位于第二位置时表达。我们得出结论，绿红杂交基因只有在色素基因序列的第2位才会引起多面体缺陷。
The X-linked red- and green-pigment genes are arranged in a head-to-tail tandem array(1-3). The colour-vision defect of deuteranomaly (in 5% of males of European descent) is associated with a 5'-green-red-3' visual-pigment hybrid gene(4,5), which may also exist in males with normal colour vision(5-7). To explain why males with a normal red, a normal green and a green-red hybrid gene may have either normal or deutan colour vision, we hypothesized that only the first two genes are expressed(8,9) and deuteranomaly results only if the green-red hybrid gene occupies the second position and is expressed preferentially over normal green-pigment genes occupying more distal positions. We used long-range PCR amplification and studied 10 deutan males (8 deuteranomalous and 2 deuteranopic) with 3 visual pigment genes (red, green and green-red hybrid) to investigate whether position of the hybrid gene in the array determined gene expression. The green-red hybrid gene was always at the second position land the first position was always occupied by the red gene). Conversely, in two men with red, green and green-red hybrid genes and normal colour vision, the hybrid gene occupied the third position. When pigment gene mRNA expression was assessed in post-mortem retinae of three men with the red, green and green-red genotype, the green-red hybrid gene was expressed only when located in the second position. We conclude that the green-red hybrid gene will only cause deutan defects when it occupies the second position of the pigment gene array.