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Biochemical Genetics (v.41, #9-10)
Substantial Genetic Effects Involved in Determination of Circulating Levels of Calciotropic Hormones in Human Pedigrees by Gregory Livshits; Constantin Yakovenko; Markus Seibel (pp. 269-289).
This paper reports the results of a series of univariate and bivariate statistical genetic analyses that were performed on a sample of nuclear and more complex pedigrees (N = 567 individuals) of an ethnically homogenous White population. Our major objectives were: (1) To quantitatively evaluate the extent and pattern of the putative genetic effects on plasma level variation and covariation of the intact parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D]; (2) To evaluate the extent of the possible genetic covariation between each of the two calciotropic hormones and two important bone mass traits, namely radiographic hands bone mineral density (BMD) and cortical index (CI). Variance component analysis, as implemented in the statistical package FISHER unambigously demonstrated that in addition to age, genetic factors contribute significantly to interindividual variation of both calciotropic hormones (37.5% for PTH and 53.3% for 25(OH)D). Complex segregation analysis strongly suggested the involvement of major gene effects into the determination of 25(OH)D levels, but was not clear cut with respect to PTH. Significant correlations between circulating levels of study hormones were found (−0.146, P < 0.05 in men and −0.194, P < 0.01 in women). However, no genetic correlation was revealed between PTH and 25(OH)D plasma concentrations. Bivariate analyses showed that familial cross correlations between PTH and BMD and CI measured at the bones of the hand were consistently statistically significant, suggesting moderate, but detectable pleiotropic genetic effects. The corresponding genetic correlations were −0.461 ± 0.153 and −0.223 ± 0.113, respectively. Circulating levels of 25(OH)D showed neither phenotypic nor genetic correlation with any of the BMD or CI variation.
Keywords: PTH; vitamin D; variance analysis; segregation analysis; BMD; cortical index
A Mini Review of the High Mobility Group Proteins of Insects by Vassiliki Aleporou-Marinou; Haroula Marinou; Theocharis Patargias (pp. 291-304).
High mobility group (HMG) proteins are an abundant class of chromosomal proteins facilitate assembly of higher order structures. The mammalian HMG proteins have been grouped into three distinct families on the basis of their characteristic functional sequence: the HMGB, the HMGN, and the HMGA family. The HMG proteins of Drosophila melanogaster and Chironomus tentans are the best characterized dipteran insect HMG proteins. Three abundant members of this group of nonhistone proteins were detected in those insects. Two of them belong to the HMGB family and one to the HMGA family. The possible relatedness of these proteins to the formation of higher order nucleoprotein structures and their possible role in the regulation of transcription is discussed.
Keywords: HMG proteins; high mobility group-like proteins; Drosophila ; Chironomus ; insects
Mitochondrial DNA Control Region and Cytochrome b Sequence Variation in the Genus Mystacoleucus Günther (Pisces: Cyprinidae: Barbinae) from China by Qing-Peng Kong; Yong-Gang Yao; Shun-You Huang; Jing-Fei Huang; Ya-Ping Zhang (pp. 305-313).
Mitochondrial DNA (mtDNA) hypervariable segment I sequences (HVSI, 471 bp) of the control region and partial cytochrome b sequences (Cytb, 403 bp) were analyzed in three tentative species of the genus Mystacoleucus in China (M. chilopterus, M. marginatus, and M. lepturus). Not more than two mutations were found in both the HVSI and Cytb fragments among the samples from M. chilopterus and M. marginatus. However, M. lepturus differed from each of them by at least 25 mutations in Cytb and 51 mutations in HVSI. Moreover, the HVSI sequence variation within M. lepturus was larger than that between M. chilopterus and M. marginatus. Given that M. chilopterus and M. marginatus are very similar in morphology, it is reasonable to consider M. chilopterus and M. marginatus as conspecific. Our results also suggest a recent radiation of M. marginatus from downstream to upstream of the Lancangjiang (Mekong) River.
Keywords: Mystacoleucus ; mtDNA; control region; cytochrome b
Cloning and Identification of a Novel Human RNPC3 Gene That Encodes a Protein with Two RRM Domains and Is Expressed in the Cell Nucleus by Enpeng Zhao; Jinsong Li; Yi Xie; Wei Jin; Zhen Zhang; Jinzhong Chen; Li Zeng; Gang Yin; Ji Qian; Hai Wu; Kang Ying; Robert Chunhua Zhao; YuMin Mao (pp. 315-323).
The RNA recognition motifs (RRM) domain is one of the most common eukaryotic protein folds. Proteins containing RRM domains function in important steps of posttranscriptional regulation of gene expression and are involved in processing and transport of mRNA precursors. Here we describe the cloning and characterization of a novel human RNPC3 gene containing two RNA recognition motifs. The 1870 bp cDNA encodes a protein with 517 amino acids. It also contains two bipartite nuclear targeting sequences, which is important for nuclear targeting for proteins, especially those functioning in the cell nucleus. The GFP location of the RNPC3 gene product shows that this protein is located in the cell nucleus. RT-PCR reveals that it is abundantly expressed in kidney and pancreas.
Keywords: human RNPC3; RRM domain; bipartite nuclear targeting sequence; RNA binding
Quantitative Trait Locus Analysis of Plasma Cholesterol and Triglyceride Levels in KK × RR F2 Mice by Jun-ichi Suto; Kenji Sekikawa (pp. 325-341).
A previous quantitative trait locus (QTL) study on hyperlipidemia in C57BL/6J × KK-A y /a F2 mice identified three significant cholesterol QTLs (Cq1 and Cq2 on chromosome 1, and Cq3 on chromosome 3), and a suggestive triglyceride QTL on chromosome 9. An alternative analysis of this study identified a novel cholesterol QTL on chromosome 9 (Cq4), and a significant triglyceride QTL on chromosome 9 (Tgq1). In the present study, QTL analysis was performed on KK × RR F2 mice. A significant cholesterol QTL (Cq5, lod score 5.6) was identified on chromosome 9, and a significant triglyceride QTL (Tgq2, lod score 4.7) was identified on chromosome 8. The Cq5 locus was mapped to a region similar to the Cq4 locus. On the other hand, the Tgq2 locus overlapped with the QTL region responsible for glucose intolerance (Giq1) that was identified in a previous study. The results suggest that a different combination of QTLs is involved in the trait when a different counterpart strain is used. Identification of distinct, but related traits in an identical chromosomal region will facilitate revealing the responsible gene.
Keywords: quantitative trait locus (QTL); cholesterol; triglyceride; apolipoprotein A-II (Apoa2); KK mouse
Genetic Polymorphism of 11 Allozyme Loci in Populations of Wall Lizards (Podarcis sp.) from the Iberian Peninsula and North Africa by Catarina Pinho; D. James Harris; Nuno Ferrand (pp. 343-359).
The taxonomy of Iberian and North African wall lizards (Podarcis sp.) has been controversial. Recently, morphological and mtDNA sequence data have provided new information on differentiation within these lacertids. To compare these results to those provided by nuclear markers, we investigated variation at 11 polymorphic protein loci using conventional electrophoresis and isoelectric focusing in 11 populations belonging to seven different mtDNA lineages. A total of 62 alleles were found. Populations belonging to the same mtDNA type presented high genetic similarity, whereas strong differentiation was observed between groups. These results are consistent with those previously obtained from morphological and mtDNA analysis and support the idea that Iberian and North African Podarcis are composed of several well-differentiated entities, some of which are already recognized as species, whereas others (belonging to the P. hispanica complex) clearly need taxonomic revision.
Keywords: Lacertidae; Podarcis hispanica ; Podarcis bocagei ; Podarcis carbonelli ; Podarcis vaucheri ; electrophoresis; isoelectric focusing; genetic polymorphism