Overlapping of MINK and CHRNE gene loci in the course of mammalian evolution.
Overlapping of genes, especially in an anti-parallel fashion, is quite rare in eukaryotic genomes. We have found a rare instance of exon overlapping involving CHRNE and MINK gene loci on chromosome 17 in humans. CHRNE codes for the epsilon subunit of the nicotinic acetylcholine receptor (AChRepsilon) whereas MINK encodes a serine/threonine kinase belonging to the GCK family. To elucidate the evolutionary trail of this gene overlapping event, we examined the genomes of a number of primates and found that mutations in the polyadenylation signal of the CHRNE gene in early hominoids led to the overlap. Upon extending this analysis to genomes of other orders of placental mammals, we observed that the overlapping occurred at least three times independently during the course of mammalian evolution. Because CHRNE and MINK are differentially expressed, the potentially hazardous mutations responsible for the exon overlap seem to have escaped evolutionary pressures by differential temporo-spatial expression of the two genes.
Dan
Ippeita
I
Division of Food Engineering, National Food Research Institute, 2-1-12, Kannondai, Tsukuba, Ibaraki 305-8642, Japan. dan@nfri.affrc.go.jp
Watanabe
Norinobu M
NM
Kajikawa
Eriko
E
Ishida
Takafumi
T
Pandey
Akhilesh
A
Kusumi
Akihiro
A
D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004285:Dogs; D019143:Evolution, Molecular; D005807:Genes, Overlapping / Q000235:genetics*; D016678:Genome; D015894:Genome, Human; D006736:Horses; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D010802:Phylogeny; D011061:Poly A / Q000235:genetics; D011323:Primates; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D011817:Rabbits; D011978:Receptors, Nicotinic / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013552:Swine; D014907:Whales
D011978:Receptors, Nicotinic; D011061:Poly A; D004247:DNA; D017346:Protein Serine-Threonine Kinases