Characterization of microsatellite markers and their correlations with growth traits in Mandarin fish (Siniperca chuatsi).

Mandarin fish (Siniperca chuatsi) is a traditionally cultured freshwater fish with high commercial value in China. To facilitate marker-assisted selection for genetic improvement of this species, 100 microsatellite markers identified in previous studies were characterized in the 25 largest and 25 smallest individuals. Twenty polymorphic loci were used to genotype 200 individuals, and the associations between their genotypes and growth traits were examined. We found that 9 genotypes at 8 loci (SC-10, Sin 135, Sin 166, AP 34-23, AP 38-11, AP 37-22, AP 37-08, and AP 37-37) were positively correlated with growth traits (body weight, body length, body height) in the mandarin fish population. The average of observed and expected heterozygosities were 0.71 and 0.59, respectively, and the average polymorphism information content value was 0.54, indicating that the population had high genetic diversity. The markers developed in this study are useful for selection of genetic breeding in this species and its related species.

Microsatellite analysis of genetic diversity and genetic structure in five consecutive breeding generations of mandarin fish Siniperca chuatsi (Basilewsky).

In this report, 10 polymorphic microsatellites were applied to assess the genetic diversity and genetic differentiation of 5 consecutive breeding generations of mandarin fish, Siniperca chuatsi (Basilewsky). The results from total number of alleles, average polymorphism information content, and average homozygosity and heterozygosity showed that the genetic diversity of the breeding population was decreasing. The genetic identity between F1 and its descendant generations (F2, F3, F4, F5) decreased (from 0.9248 to 0.8803), while the genetic distance (from 0.0782 to 0.1275) and fixation index (from 0.03796 to 0.07393) increased. The allele frequency of SS181-235 and SS211-246 changed regularly in the 5 breeding generations, and they may be negatively associated with the selected trait, which needs to be confirmed by further research. Our study indicated that selective breeding was an efficient strategy for mandarin fish. In the process of breeding, some deleterious genes were phased out, and the genetic structure of the breeding populations became stable.

Microsatellite DNA markers and their correlation with growth traits in mandarin fish (Siniperca chuatsi).

The mandarin fish (Siniperca chuatsi) is a traditionally cultured freshwater fish with high commercial value in China. To facilitate marker-assisted selection in genetic improvement of this species, 120 microsatellite markers from the literature were characterized in the 25 largest and 25 smallest individuals. Eighteen polymorphic loci were then used to genotype 200 individuals, and the associations between their genotypes and growth traits were examined. We found that eight genotypes of six loci (AP 37-06, AP 37-11, AP 37-16, AP 37-48, AP 38-32, and AP 39-05) were positively correlated with growth traits (body weight, length, and height) in the mandarin fish population. The average observed and expected heterozygosities were 0.68 and 0.59, respectively, and the average PIC value was 0.50, indicating a population with high genetic diversity. Therefore, these markers could be useful for assisted selection in genetic breeding of this species and its related species.

[Sequence analysis of SSU rDNA variable regions of Leishmania isolates from hilly foci and plain foci of China].

OBJECTIVE: To analyze the sequence difference of the SSU rDNA variable regions of Leishmania isolates from hilly foci and plain foci of China. METHODS: Specific SSU rDNA fragments from nuclear DNA of five Leishmania species and isolates were amplified by PCR. The amplified DNA fragments were cloned into pGEMR-T Easy vector. The specific fragments were sequenced by the automated DNA sequencer. RESULTS: Sequence analysis showed that the amplified DNA fragments of five Leishmania species and isolates were all 392 bp in length, point mutations were located in the two unique sequence (UQ-I and UQ-II); L. d. SC10 and L. d. GS7 had two same point mutations in UQ-II, only L. d. GS7 had one in UQ-I; no insertion/deletion. CONCLUSION: Sequence difference of the SSU rDNA variable region existed between Leishmania isolates from hilly foci and plain foci; The sequences of the SSU rDNA variable regions of L. d. SD2 isolate and L. infantum were identical.

Protein tyrosine phosphatase containing SH2 domains: characterization, preferential expression in hematopoietic cells, and localization to human chromosome 12p12-p13.

Protein tyrosine phosphorylation has been implicated in the growth and functional responses of hematopoietic cells. Recently, approaches have been developed to characterize the protein tyrosine phosphatases that may contribute to regulation of protein tyrosine phosphorylation. One novel protein tyrosine phosphatase was expressed predominantly in hematopoietic cells. Hematopoietic cell phosphatase encodes a 68-kDa protein that contains a single phosphatase conserved domain. Unlike other known protein tyrosine phosphatases, hematopoietic cell phosphatase contains two src homology 2 domains. We also cloned the human homolog, which has 95% amino acid sequence identity. Both the murine and human gene products have tyrosine-specific phosphatase activity, and both are expressed predominantly in hematopoietic cells. Importantly, the human gene maps to chromosome 12 region p12-p13. This region is associated with rearrangements in approximately 10% of cases of acute lymphocytic leukemia in children.

Hematopoietic cells express two forms of lyn kinase differing by 21 amino acids in the amino terminus.

cDNAs for the murine lyn protein tyrosine kinase gene were cloned from mouse bone marrow-derived monocytic cells. Comparison of the human and murine genes demonstrated a 94% homology in peptide sequence. Comparable to the human gene, murine lyn was found to be expressed in myeloid and B-lymphoid lineage cells. During the cloning, two types of cDNAs were obtained that differed by the presence (lynA) or absence (lynB) of 63 bp within the amino-terminal coding region of the gene. The genomic structure of the murine lyn gene demonstrates that the two types of lyn transcripts are derived from alternative splicing utilizing an internal splice donor site. Transcripts for both forms were found to be expressed in myeloid cells. lyn-specific antisera detected comparable levels of proteins of 56 and 53 kDa in hematopoietic cells. these 56- and 53-kDa proteins comigrated with proteins produced by in vitro translation or in vivo expression of the lynA and lynB cDNAs, respectively. The two forms had comparable in vitro kinase activities in immunoprecipitates and showed similar peptide patterns, with partial V8 digestion of the in vitro-phosphorylated proteins. The potential significance of the two lyn proteins is discussed.

Regulation of MHC class II gene expression in macrophages by hematopoietic colony-stimulating factors (CSF). Induction by granulocyte/macrophage CSF and inhibition by CSF-1.

CSF-1 and granulocyte/monocyte CSF (GM-CSF) were shown to modulate the levels of Ia gene and protein expression in bone marrow-derived macrophages (BMM). Recombinant GM-CSF induced high levels of Ia expression, similar to the levels induced by INF-gamma, while IL-3 had no effect. In contrast, recombinant CSF-1 not only suppressed the basal levels of Ia gene and protein expression in BMM, but also inhibited the induction of Ia by IFN-gamma and GM-CSF. Basal levels of Ia were not inhibited by recombinant CSF-1 until after 16-24 h of culture, suggesting an indirect mechanism of suppression. IFN-alpha/beta and PGE2 were shown not to be involved in the CSF-1 inhibition of basal levels of Ia expression. However, the CSF-1-mediated suppression of both the basal levels of Ia expression and the induction of Ia in BMM by IFN-gamma and GM-CSF did correlate with the induction of cellular proliferation. These data imply that in addition to regulating hematopoiesis, CSFs may regulate the initiation of the immune response through their effects on Ia expression in macrophages.

Cloning of the murine c-fgr proto-oncogene cDNA and induction of c-fgr expression by proliferation and activation factors in normal bone marrow-derived monocytic cells.

Normal murine bone marrow-derived monocytic cells were found to contain transcripts for c-fgr and hck, two members of the src family of proto-oncogene tyrosine kinases. While hck transcripts were increased only in response to bacterial lipopolysaccaride (LPS), expression of c-fgr was transiently induced both by the monocyte/macrophage proliferative stimulus CSF-1 as well as by signals which activate monocytic cells to functional states (granulocyte-macrophage colony stimulating factor (GM-CSF), LPS, and gamma interferon). These data suggest that these highly related tyrosine kinases may differentially mediate the effects of distinct monocyte/macrophage stimuli; and, that the c-fgr proto-oncogene in particular, which in normal cells is selectively expressed in monocytes, may play a pivotal functional role in these cells. A 2.2 kb cDNA clone, containing a 1551 base pair open reading frame encoding a protein with all of the hallmarks of a protein-tyrosine kinase, was isolated from a cDNA library made from RNA of CSF-1-stimulated bone marrow-derived monocytic cells. This clone had the highest homology to v-fgr and likely encodes the murine c-fgr transcript expressed by normal monocytes. However, when compared to sequences previously reported for human c-fgr derived from EBV-transformed B cells and heterogeneous peripheral blood cells, the c-fgr cDNA derived from normal murine monocytic cells differed significantly in sequence from amino acids 12-62 in the amino terminal domain of the protein which may mediate the substrate specificity and subcellular location of the src family of protein-tyrosine kinases.