Haigh Andrew J, Lloyd Vett K
Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
Genome. 2006 Aug;49(8):1043-6. doi: 10.1139/g06-042.
Genomic imprinting is a process that genetically distinguishes maternal and paternal genomes, and can result in parent-of-origin-dependent monoallelic expression of a gene that is dependent on the parent of origin. As such, an otherwise functional maternally inherited allele may be silenced so that the gene is expressed exclusively from the paternal allele, or vice versa. Once thought to be restricted to mammals, genomic imprinting has been documented in angiosperm plants (J.L. Kermicle. 1970. Genetics, 66: 69-85), zebrafish (C.C. Martin and R. McGowan. 1995. Genet. Res. 65: 21-28), insects, and C. elegans (C.J. Bean, C.E. Schaner, and W.G. Kelly. 2004. Nat. Genet. 36: 100-105.). In each case, it appears to rely on differential chromatin structure. Aberrant imprinting has been implicated in various human cancers and has been detected in a number of cloned mammals, potentially limiting the usefulness of somatic nuclear transfer. Here we show that genomic imprinting associated with a mini-X chromosome is lost in Drosophila melanogaster clones.
基因组印记是一种从基因上区分母本和父本基因组的过程,可导致基因的亲本来源依赖性单等位基因表达,该表达取决于基因的亲本来源。因此,一个原本功能正常的母本遗传等位基因可能会被沉默,从而使该基因仅从父本等位基因表达,反之亦然。基因组印记曾被认为仅限于哺乳动物,如今在被子植物(J.L. 克米克尔。1970年。《遗传学》,66卷:69 - 85页)、斑马鱼(C.C. 马丁和R. 麦高恩。1995年。《遗传学研究》,65卷:21 - 28页)、昆虫以及秀丽隐杆线虫(C.J. 比恩、C.E. 沙纳和W.G. 凯利。2004年。《自然遗传学》,36卷:100 - 105页)中都有记载。在每种情况下,它似乎都依赖于不同的染色质结构。异常的印记与多种人类癌症有关,并且在一些克隆哺乳动物中也被检测到,这可能会限制体细胞核移植的实用性。在此我们表明,与微型X染色体相关的基因组印记在黑腹果蝇克隆中丢失。