Tolan D R, Niclas J, Bruce B D, Lebo R V
Biological Sciences Center, Boston University, MA 02215.
Am J Hum Genet. 1987 Nov;41(5):907-24.
The aldolase genes represent an ancient gene family with tissue-specific isozymic forms expressed only in vertebrates. The chromosomal locations of the aldolase genes provide insight into their tissue-specific and developmentally regulated expression and evolution. DNA probes for the human aldolase-A and -C genes and for an aldolase pseudogene were used to quantify and map the aldolase loci in the haploid human genome. Genomic hybridization of restriction fragments determined that all the aldolase genes exist in single copy in the haploid human genome. Spot-blot analysis of sorted chromosomes mapped human aldolase A to chromosome 16, aldolase C to chromosome 17, the pseudogene to chromosome 10; it previously had mapped the aldolase-B gene to chromosome 9. All loci are unlinked and located on to two pairs of morphologically similar chromosomes, a situation consistent with tetraploidization during isozymic and vertebrate evolution. Sequence comparisons of expressed and flanking regions support this conclusion. These locations on similar chromosome pairs correctly predicted that the aldolase pseudogene arose when sequences from the aldolase-A gene were inserted into the homologous aldolase location on chromosome 10.
醛缩酶基因代表了一个古老的基因家族，其组织特异性同工酶形式仅在脊椎动物中表达。醛缩酶基因的染色体定位有助于深入了解其组织特异性和发育调控的表达及进化。使用人类醛缩酶A和C基因以及一个醛缩酶假基因的DNA探针来定量和定位单倍体人类基因组中的醛缩酶基因座。限制性片段的基因组杂交确定所有醛缩酶基因在单倍体人类基因组中以单拷贝形式存在。对分选染色体的斑点印迹分析将人类醛缩酶A定位到16号染色体，醛缩酶C定位到17号染色体，假基因定位到10号染色体；之前已将醛缩酶B基因定位到9号染色体。所有基因座均不连锁，且位于两对形态相似的染色体上，这种情况与同工酶和脊椎动物进化过程中的四倍体化一致。对表达区域和侧翼区域的序列比较支持这一结论。在相似染色体对上的这些定位正确地预测了醛缩酶假基因是在醛缩酶A基因的序列插入到10号染色体上同源的醛缩酶位置时产生的。
