Phylogenetic and size constrains on cranial ontogenetic allometry of spiny rats (Echimyidae, Rodentia).

Analysis of ontogenetic development is crucial for understanding the emergence of phenotypic discrepancies between animal taxa. The study of allometric trajectories within a phylogenetic context is a feasible approach to assess the morphological change across different evolutionary lineages. Here, we report the disparity of multivariate ontogenetic allometry in the Echimyidae, a taxonomically diverse rodent family, as well as the effects of size on the evolution of skull ontogeny. The ontogenetic trajectories of 15 echimyid operational taxonomic unities (12 genera plus one genus with three species) belonging to all subfamilies and major clades, when plotted in allometric space, revealed strong and significant phylogenetic signals. Allometric trajectories were found to be constrained by phylogenetic ancestry, with changes approximately adjusting to a Brownian motion model of evolution. Moreover, the occupation of allometric space by echimyid taxa was significantly correlated with adult size rather than with shape, suggesting that the variation in adult size might result in critically intrinsic and structural constraints on allometric coefficients. These findings disagreed with the hypothesis that allometric disparities might be mainly adaptive with undetectable phylogenetic signals.

Association of TP53 polymorphisms on the risk of Wilms tumor.

BACKGROUND: Molecular factors influencing Wilms tumor (WT) development remain largely unknown. TP53 mutations seem to be restricted to the anaplastic WT subtype. However, TP53 polymorphisms do not have a defined role in the disease. PROCEDURE: To assess the impact of TP53 mutations and polymorphisms (PIN2, PIN3, and PEX4) on risk of development, age at diagnosis, and survival in WT, we analyzed 46 blood DNA samples and 31 fresh tumor DNA samples from 52 patients with WT. Sequencing of TP53 exons 2-11 was performed. RESULTS: Tumor DNA analysis revealed TP53 pathogenic missense mutations (p.V197M, p.R213Q, p.R248W, and p.R337C) in four samples (12.9%). Blood DNA samples revealed a novel intronic mutation, IVS2 + 37C > T, in one patient (2.2%). Bilaterality was associated with a twofold decrease in survival (P = 0.00037). Diffuse anaplasia also presented a lower survival probability compared to patients with non-anaplastic tumors, or with focal anaplasia (P = 0.045). Patients with a TP53 somatic mutation showed survival probability of 37.5% versus 85.0% for patients with no somatic mutations, although the difference was not statistically significant (P = 0.0706). PIN3 duplicated allele was associated with a 20-month later mean age at diagnosis (P = 0.0084). TP53 PEX4 C allele showed an increased risk for WT development (P = 0.0379). No relationship was found between survival and gender, age at diagnosis, or the less frequent alleles of PIN2, PIN3, and PEX4. CONCLUSIONS: Our results demonstrate an association between PIN3 and age at diagnosis, as well as an association of PEX4 and risk of development of WT.

Genetic diversity of neotropical primates: phylogeny, population genetics, and animal models for infectious diseases.

The classification of neotropical primates has been controversial, and different arrangements have been proposed based on disparate taxonomic criteria and on the traits selected for elucidating phylogenetic reconstructions, like morphologic characters, nuclear DNA and mitochondrial DNA. Population studies of some neotropical primates have been useful for assessing their extant genetic variability and for understanding their social structure and dynamics. Finally, neotropical primates have become valuable models for some human infectious deseases, especially for HIV studies related to viral resistance. In this review, we comment on these aspects that make neotropical primates a group of highly valuable species for basic and applied research.

The GLI-Kruppel family of human genes.

Previous characterization of GLI, a gene found to be amplified and expressed in a subset of human brain tumors, revealed the presence of five tandem zinc fingers related to those of Krüppel (Kr), a Drosophila segmentation gene of the gap class. We have used the GLI cDNA as a molecular probe to isolate related sequences from the human genome. Partial characterization of six related loci, including sequence determination, expression studies, and chromosome localization, revealed that each locus could encode a separate finger protein. The predicted proteins all had similar H-C links, i.e., a conserved stretch of 9 amino acids connecting the C-terminal histidine of one finger to the N-terminal cysteine of the next. On the basis of amino acid sequence and intron-exon organization, the genes could be placed into one of two subgroups: the GLI subgroup (with the consensus finger amino acid sequence [Y/F]XCX3GCX3[F/Y]X5LX2HX3-4H[T/S]GEKP) or the Kr subgroup (with the consensus finger amino acid sequence [Y/F]XCX2CX3FX5LX2HXRXHTGEKP). Unlike GLI or Kr, most of the newly isolated genes were expressed in many adult tissues. The predicted proteins probably control the expression of other genes and, by analogy with Kr and GLI, may be important in human development, tissue-specific differentiation, or neoplasia.

The primates of the Neotropics: genomes and chromosomes.

The classification of neotropical primates has been controversial. Different arrangements have been proposed, depending on taxonomic criteria and on the traits selected for phylogenetic reconstructions. These include gross morphologic characters, karyotypic attributes and DNA sequence data of nuclear and mitochondrial genes and of repetitive genomic components. These approaches have substantially clarified the main intergeneric relationships although several intrageneric arrangements still remain to be elucidated. In this review, we compare karyologic and molecular data of this speciose group.

Cytochrome b polymorphisms and population structure of two species of Alouatta (Primates).

We carried out a phylogenetic and population study in Alouatta caraya and Alouatta belzebul based on cytochrome b DNA sequence data. Maximum Parsimony and Median-Joining analyses grouped A. caraya from different localities showing a population structure in accordance with geographic distribution. The relation between A. caraya haplotypes could be explained with respect to the species range in the Cerrado, one of the most ancient morphoclimatic domains of South America, and the Chaco. Conversely, A. belzebul from the Amazonas and Atlantic forests grouped in a paraphyletic arrangement without an evident geographic pattern. Recent geologic events resulting in the separation of A. belzebul might explain why these geographically distant groups shared similar haplotypes and why ancestral polymorphisms might have been maintained in this species. Time of divergence estimates indicated that the splitting of the Alouatta lineage leading to A. caraya occurred some 4.58 MYA while the lineage leading to A. belzebul emerged 4.14 MYA.

Detection of BCR-ABL transcripts in chronic myeloid leukaemia by nested PCR.

Polymerase chain reaction (PCR) is a powerful and rapid method for specifically detecting BCR-ABL rearrangement by amplification of the complementary DNA (cDNA) produced by reverse transcription of BCR-ABL mRNA. We studied 29 patients for detecting the presence of BCR-ABL transcripts before and after bone marrow transplantation (BMT). Our sample was composed of two different groups of patients: one group (n = 18) was studied by serial follow-ups before and after BMT; a second group (n = 11) was studied several years after BMT. Detection of BCR-ABL was carried out with different primer sets at different periods of the clinical outcome of chronic myeloid leukaemia (CML). A comparison of PCR data and clinical-haematological conditions showed clear differences between patients. In the first group, eight patients showed a positive correlation between a favourable clinical outcome and molecular remission. Conversely, in the second group, six patients were BCR-ABL positive between 20 and 117 months after BMT, while only two of these patients showed signs of clinical relapse. Among all patients whose isoforms were known at some time during the course of CML, the more frequent isoform was b3a2. These results were compared to previous findings in the literature on diagnosis, outcome and prognosis of CML.

Molecular analysis of HPRT1(+) somatic cell hybrids derived from a carrier of an HPRT1 mutation responsible for Lesch-Nyhan syndrome.

Heterozygous carriers of HPRT1 mutations responsible for Lesch-Nyhan syndrome can be detected by analysis of somatic cell hybrids derived from peripheral blood lymphocytes and Hprt1-negative cells of rodent origin followed by selection in culture medium containing hypoxanthine, aminopterine, and thymidine (HAT). The parental origin of the X chromosome containing the normal HPRT1 allele in HPRT1(+) hybrid cell lines can be determined by molecular haplotyping attributable to highly polymorphic X-linked markers. We used this procedure to study a presumed carrier whose paternal active X chromosome always segregated in the cell hybrids derived from her. Conversely, her maternal X chromosome was systematically absent in most cell hybrids, or when present, it was inactive and coexisted with an active, paternal X chromosome. These results clearly demonstrated that the proband was a heterozygous carrier of a mutation responsible for HPRT1 deficiency.

Identification of three novel RB1 mutations in Brazilian patients with retinoblastoma by "exon by exon" PCR mediated SSCP analysis.

AIMS: To carry out a retrospective study, screening for mutations of the entire coding region of RB1 and adjacent intronic regions in patients with retinoblastoma. METHODS: Mutation screening in DNA extracts of formalin fixed, paraffin wax embedded tissues of 28 patients using combined "exon by exon" polymerase chain reaction mediated single strand conformational polymorphism analysis, followed by DNA sequencing. RESULTS: Eleven mutations were found in 10 patients. Ten mutations consisted of single base substitutions; 10 were localised in exonic regions (eight nonsense, one missense, and one frameshift) and another one in the intron-exon splicing region. Three novel mutations were identified: a 2 bp insertion in exon 2 (g.5506-5507insAG, R73fsX77), a G to A transition affecting the last invariant nucleotide of intron 13 (g.76429G>A), and a T to C transition in exon 20 (g.156795T>C, L688P). In addition, eight C to T transitions, resulting in stop codons, were found in five different CGA codons (g.64348C>T, g.76430C>T, g.78238C>T, g.78250C>T, and g.150037C>T). Although specific mutation hotspots have not been identified in the literature, eight of the 11 mutations occurred in CGA codons and seven fell within the E1A binding domains (codons 393-572 and 646-772), whereas five were of both types-in CGA codons within E1A binding domains. CONCLUSIONS: CGA codons and E1A binding domains are apparently more frequent mutational targets and should be initially screened in patients with retinoblastoma. Paraffin wax embedded samples proved to be valuable sources of DNA for retrospective studies, providing useful information for genetic counselling.

Translocation 11;14 in three children with acute lymphoblastic leukemia of T-cell origin.

Clinical, karyotypic, immunophenotypic, and molecular profiles of three TALL cases carrying a t(11;14) are discussed and compared with data in the literature. As previously reported, t(11;14)(p13;q11) was associated in one patient with a TALL profile of intermediate stage of maturation (CD7+, CD4+, CD8+). However, the same translocation was found to be present in another patient with a more immature, pro-TALL profile (CD7+, CD4-, CD8-). Both patients showed molecular rearrangements of the TCR beta chain gene. A third patient, with a very immature pro-TALL profile (CD34+, CD7+, CD4-, CD8-), carrying a t(11;14)(p15;q11), showed molecular rearrangements of the TCR beta and gamma chain genes, while the IgH chain genes were in germline configuration. Our data indicate that t(11;14) can also be present in TALLs of more immature stages of intrathymic development; the significant factor determining the clinical behavior of TALLs is apparently related more to cell differentiation than to the presence of this chromosome rearrangement.

Detection of BCR-ABL transcripts by multiplex and nested PCR in different haematological disorders.

Single-step Multiplex RT-PCR was used as a rapid and highly sensitive method for screening patients with myeloproliferative conditions and ALL for the presence of underlying BCR-ABL gene fusions. Positive and negative results obtained with the multiplex assay were subsequently confirmed by nested PCR. We studied 21 patients for detecting the presence of b3a2, b2a2 and e1a2 BCR-ABL transcripts at diagnosis and following treatment with different therapeutical procedures. These studies allowed the molecular characterisation of patients with different haematological disorders and for demonstrating BCR-ABL transcripts in Ph-CML. In a Ph+ CML patient, a switch of isoforms was detected after bone marrow transplantation and infusion with donor lymphocytes, implying substitution of e1a2 for b3a2 coexisting with a myeloid/lymphoid biphenotypic profile. In ALL, one Ph+ patient showed coexpression of e1a2 and b2a2 at diagnosis followed by persistence of e1a2 after bone marrow transplantation. Our results were compared to previous findings in the literature on molecular diagnosis of leukaemias.

Chromosome studies in Chiropotes satanas utahicki hershkovitz, 1985 (cebidae, platyrrhini): A comparison with Chiropotes satanas chiropotes.

Karyological characterizations of C. s. utahicki (2n = 54) and C. s. chiropotes (2n = 54) showed that these two subspecies are chromosomally very similar. In a single, isolated specimen of C s. utahicki, however, a derived, biarmed, chromosome 14 was found in the heterozygous condition. This variant chromosome was identical with pair 10 in C. s. chiropotes in which this chromosome type was apparently fixed. Chromosome differences between these subspecies might be transitional, leading to the establishment of two different karyomorphic populations derived from a once uniform karyotypic group that split into separate allopatric subspecies. © 1992 Wiley-Liss, Inc.

Prevalence of hepatitis C virus among users attending a voluntary testing centre in Rio Grande, southern Brazil: predictive factors and hepatitis C virus genotypes.

We estimated the prevalence of hepatitis C (HCV) infection and associated risk factors in 750 individuals attending the Voluntary Counseling and Testing Center of Rio Grande (VCT/RG), in Southern Brazil, and identified viral genotypes. Demographic data and risk factors for HCV transmission were also collected and analysed. Anti-HCV antibody-positive individuals were tested for HCV-RNA and genotyped by sequencing the 5' untranslated region of the viral genome. Prevalence estimates of anti-HCV and HCV-RNA were 6% and 5.5%, respectively. We identified genotypes 1 (67%), 2 (2%) and 3 (31%); the latter was more prevalent than in other regions of Brazil. Anti-HCV prevalence in VCT/RG users was similar to previous reports. Age, previous blood transfusion, sexual orientation and injecting drug use were independent predictors of HCV infection. The presence of multiple risk factors was also associated with a higher risk for HCV infection. HCV genotype was not associated with any variable analysed in this study.

Chromosomes and spermatozoa of the African great apes.

We have analysed the chromosome constitution of 8 chimpanzees (Pan troglodytes), 3 pygmy chimpanzees (Pan paniscus), and 16 gorillas (Gorilla gorilla). In the chimpanzees, the frequency of brilliant Q-band polymorphisms accounted for 8.85 regions per individual, and in the gorilla 14.9, whereas in man it was only 2.9-4.6. Variation in the amount of constitutive heterochromatin was also observed, and the gorilla appeared to be the most variable of all. A detailed analysis of the spermatozoa of the African apes showed that the gorilla produced pleiomorphic spermatozoa. As the animals under investigation were phenotypically normal, of proven fertility, and were kept in unheated cages, it is probable that gorillas, like human males, normally exhibit pleiomorphic spermatozoa. This makes it unlikely that clothing-induced hyperthermia could account for pleiomorphic spermatozoa in man. The modal cell types in the ejaculates of men and gorillas were also morphologically identical. The less frequent cell types defined as morphologically abnormal spermatozoa were also very similar and occurred in similar proportions. It is therefore impossible to distinguish between man and the gorilla by a simple examination of the ejaculate, although it is possible to distinguish between man and the chimpanzees or between the gorilla and the chimpanzees. Both species of chimpanzee produced identical spermatozoa. With quinacrine fluorescence, F-bodies were observed in the sperm head of the chimpanzees and the gorilla. In the chimpanzee and the pygmy chimpanzee, F-bodies correspond to brilliant autosomal regions, whereas in the gorilla they probably correspond both the the autosomes and the Y chromosome. There was no consistently visible F-body in the sperm head of the chimpanzee or the gorilla; in the pygmy chimpanzee, one fluorescent region appeared, and it probably corresponded to a brilliant region in autosomal pair No. 23.

Late DNA replication in rhesus monkey (Macaca mulatta) chromosomes.

A study of the pattern of late DNA replication in rhesus monkey chromosomes showed evident similarities with man. This must be a consequence of the evolutionary conservation of replication patterns in primate chromosomes, as it has been demonstrated in the great apes, in Cebus, and man. However, the pattern of late replication of the allocyclic X chromosome in lymphocytes of female rhesus monkey was identical with the fibroblast pattern in man, and with the pattern found in only 5 to 20% of human lymphocytes.