Südhof T C, Russell D W, Goldstein J L, Brown M S, Sanchez-Pescador R, Bell G I
Science. 1985 May 17;228(4701):893-5. doi: 10.1126/science.3873704.
The amino acid sequences of the human low-density lipoprotein (LDL) receptor and the human precursor for epidermal growth factor (EGF) show 33 percent identity over a stretch of 400 residues. This region of homologous is encoded by eight contiguous exons in each respective gene. Of the nine introns that separate these exons, five are located in identical positions in the two protein sequences. This finding suggests that the homologous region may have resulted from a duplication of an ancestral gene and that the two genes evolved further by recruitment of exons from other genes, which provided the specific functional domains of the LDL receptor and the EGF precursor.
人类低密度脂蛋白（LDL）受体和人类表皮生长因子（EGF）前体的氨基酸序列在一段400个残基的区域内显示出33%的同源性。这个同源区域在各自的基因中由八个连续的外显子编码。在分隔这些外显子的九个内含子中，有五个位于这两种蛋白质序列的相同位置。这一发现表明，同源区域可能是由一个祖先基因的复制产生的，并且这两个基因通过从其他基因招募外显子而进一步进化，这些外显子提供了LDL受体和EGF前体的特定功能结构域。
