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1.
The alpha-like globin gene cluster in rabbits contains embryonic zeta-
globin genes, an adult alpha-globin gene, and theta-globin genes of
undetermined function. The basic arrangement of genes, deduced from
analysis of cloned DNA fragments, is 5'-zeta 0-zeta 1-alpha 1-theta 1- zeta
2-zeta 3-theta 2-3'. However, the pattern of restriction fragments
containing zeta- and theta-globin genes varies among individual rabbits.
Analysis of BamHI fragments of genomic DNA from 24 New Zealand white
rabbits revealed eight different patterns of fragments containing
zeta-globin genes. The large BamHI fragments containing genes zeta 0 and
zeta 1 are polymorphic in length, whereas a 1.9-kb fragment containing the
zeta 2 gene and the 3.5-kb fragment containing the zeta 3 gene do not vary
in size. In contrast to this constancy in the size of the restriction
fragments, the copy number of the zeta 2 and zeta 3 genes does vary among
different rabbits. No length polymorphism was detected in the BamHI
fragments containing the theta-globin genes, but again the copy number
varies for restriction fragments containing the theta 2 gene. The alpha 1-
and theta 1-globin genes are located in a nonpolymorphic 7.2-kb BamHI
fragment. The combined data from hybridization with both zeta and theta
probes shows that the BamHI cleavage pattern does not vary within the
region 5'-alpha 1-theta 1- zeta 2-zeta 3-theta 2-3', but the pattern
genomic blot-hybridization patterns for the progeny of parental rabbits
with different zeta-globin gene patterns shows that the polymorphic
patterns are inherited in a Mendelian fashion. Two different haplotypes
have been mapped based on the genomic blot-hybridization data. The
variation in the alpha-like globin gene cluster in the rabbit population
results both from differences in the copy number of the duplication block
containing the zeta-zeta-theta gene set and from the presence or absence of
polymorphic BamHI sites.
相似文献
2.
Assignment of orthologous relationships among mammalian alpha-globin genes by examining flanking regions reveals a rapid rate of evolution 总被引:1,自引:0,他引:1
In order to study the relationships among mammalian alpha-globin genes, we
have determined the sequence of the 3' flanking region of the human alpha 1
globin gene and have made pairwise comparisons between sequenced
alpha-globin genes. The flanking regions were examined in detail because
sequence matches in these regions could be interpreted with the least
complication from the gene duplications and conversions that have occurred
frequently in mammalian alpha-like globin gene clusters. We found good
matches between the flanking regions of human alpha 1 and rabbit alpha 1,
human psi alpha 1 and goat I alpha, human alpha 2 and goat II alpha, and
horse alpha 1 and goat II alpha. These matches were used to align the
alpha-globin genes in gene clusters from different mammals. This alignment
shows that genes at equivalent positions in the gene clusters of different
mammals can be functional or nonfunctional, depending on whether they
corrected against a functional alpha-globin gene in recent evolutionary
history. The number of alpha-globin genes (including pseudogenes) appears
to differ among species, although highly divergent pseudogenes may not have
been detected in all species examined. Although matching sequences could be
found in interspecies comparisons of the flanking regions of alpha- globin
genes, these matches are not as extensive as those found in the flanking
regions of mammalian beta-like globin genes. This observation suggests that
the noncoding sequences in the mammalian alpha-globin gene clusters are
evolving at a faster rate than those in the beta-like globin gene clusters.
The proposed faster rate of evolution fits with the poor conservation of
the genetic linkage map around alpha-globin gene clusters when compared to
that of the beta-like globin gene clusters. Analysis of the 3' flanking
regions of alpha-globin genes has revealed a conserved sequence
approximately 100-150 bp 3' to the polyadenylation site; this sequence may
be involved in the expression or regulation of alpha-globin genes.
相似文献
3.
Falcón R Carbonell GV Figueredo PM Butião F Saridakis HO Pelayo JS Yano T 《Journal of applied microbiology》2003,95(2):273-278
AIMS: Potential virulence factors produced by culture filtrates of Plesiomonas shigelloides isolated from water were investigated. METHODS AND RESULTS: Culture filtrates of P. shigelloides strains were assayed for cytotoxic activity in CHO (Chinese hamster ovary), Vero (African green monkey kidney), HeLa (human cervix), HT29 (human epithelial intestinal) and SK6 (swine epithelial kidney) cells. Microscopic analyses revealed intensive cytoplasmic vacuolation including cell rounding and swelling, with gradual destruction of the monolayer in filtrate-treated cells. Neutral red assays showed that CHO, HeLa and Vero cells were the most sensitive to the vacuolating activity, which was evident within 30 min of culture filtrate exposure. This activity was inactived by heating at 56 degrees C for 15 min and partially neutralized by antiserum to the cytotoxin of Aeromonas hydrophila. All P. shigelloides strains had a cell-associated haemolysin in the agar plate assay. Three isolates were found to produce a cell-free haemolytic activity at 37 degrees C. In the suckling mouse test, two P. shigelloides culture supernatants were positive for enterotoxic activity. CONCLUSIONS: P. shigelloides culture filtrates isolated from aquatic environment cause intracellular vacuolation on mammalian cells, and produce haemolytic and enterotoxic activities. SIGNIFICANCE AND IMPACT OF THE STUDY: This work revealed the presence of putative virulence factors that could be associated with human infections involving Plesiomonas strains. 相似文献
4.
5.
Out of Africa and back again: nested cladistic analysis of human Y chromosome variation 总被引:18,自引:3,他引:15
Hammer MF; Karafet T; Rasanayagam A; Wood ET; Altheide TK; Jenkins T; Griffiths RC; Templeton AR; Zegura SL 《Molecular biology and evolution》1998,15(4):427-441
We surveyed nine diallelic polymorphic sites on the Y chromosomes of 1,544
individuals from Africa, Asia, Europe, Oceania, and the New World.
Phylogenetic analyses of these nine sites resulted in a tree for 10
distinct Y haplotypes with a coalescence time of approximately 150,000
years. The 10 haplotypes were unevenly distributed among human populations:
5 were restricted to a particular continent, 2 were shared between Africa
and Europe, 1 was present only in the Old World, and 2 were found in all
geographic regions surveyed. The ancestral haplotype was limited to African
populations. Random permutation procedures revealed statistically
significant patterns of geographical structuring of this paternal genetic
variation. The results of a nested cladistic analysis indicated that these
geographical associations arose through a combination of processes,
including restricted, recurrent gene flow (isolation by distance) and range
expansions. We inferred that one of the oldest events in the nested
cladistic analysis was a range expansion out of Africa which resulted in
the complete replacement of Y chromosomes throughout the Old World, a
finding consistent with many versions of the Out of Africa Replacement
Model. A second and more recent range expansion brought Asian Y chromosomes
back to Africa without replacing the indigenous African male gene pool.
Thus, the previously observed high levels of Y chromosomal genetic
diversity in Africa may be due in part to bidirectional population
movements. Finally, a comparison of our results with those from nested
cladistic analyses of human mtDNA and beta-globin data revealed different
patterns of inferences for males and females concerning the relative roles
of population history (range expansions) and population structure
(recurrent gene flow), thereby adding a new sex-specific component to
models of human evolution.
相似文献
6.
Francisco Guil Sandra Agudín Nuria El-Khadir Mariana Fernandez-Olalla Juan Figueredo Francisco G. Domínguez Paloma Garzon Gregorio Gonzalez Jaime Muñoz-Igualada Javier Oria Fernando Silvestre 《European Journal of Wildlife Research》2010,56(4):633-640
Camera trapping is the most used method for surveying medium-sized carnivores in Spain. The main target for these surveys has been the Iberian lynx, the most endangered cat in the world. The Iberian lynx conservation program has received the largest EU LIFE projects grant. So, efficiency is a key goal for managing this grant. During 2003 and 2007, we have applied these funds to the survey of the Iberian lynx in Eastern Sierra Morena (Spain). Using two different techniques, we have studied both to see which is the most efficient. The survey developed in active latrines resulted more efficient than that of scent stations and live prey camera trapping throughout the years, although there has been a variation between years. Otherwise, the live prey method has been the one providing the greatest speed and number of pictures per entrance. We suggest that camera-trapping surveys can be improved in terms of efficiency for a wide range of species, or at least for the Iberian lynx. To improve the results, cameras might be placed in relation to breeding territories. With this determinant, camera-trapping surveys would be shorter than 120 days. Finally, we suggest how those surveys for medium carnivores should be designed. 相似文献
7.
Genetic diversification of offspring represents a bet-hedging strategy that evolved as an adaptation to unpredictable environments. The benefits of sexual reproduction come with severe costs. For example, each offspring only carries half of each parent's genetic makeup through direct descent. The lower the reproductive rate, the more substantial the cost when considering the proportion of genes represented in subsequent generations. Positive assortative mating represents a conservative bet-hedging strategy that offsets some of these costs and preserves coadapted genomes in stable and predictable environments, whereas negative assortative mating serves the inverse function of genetic diversification in unstable and unpredictable environments. 相似文献
8.
Hernández HM Figueredo M Garrido N Sánchez L Sarracent J 《International journal for parasitology》2005,35(13):1333-1337
Trichomonosis, caused by the protozoan parasite Trichomonas vaginalis, is one of the most frequent sexually transmitted diseases and is widely spread in all continents. Trichomonas vaginalis as well as other protozoan organisms have high levels of proteolitic activity mainly of the cysteine-proteinase type. This activity is necessary for recognition and adhesion of the parasite to the superficial epithelial cells of the host. In the present study, we show that intranasal immunisation with a 62 kDa cysteine-proteinase purified from T. vaginalis excretion-secretion products in combination with cholera toxin or with synthetic oligodeoxynucleotides (ODN) that contain unmethylated CpG motifs (CpG-ODN) elicits 62kDa specific IgG and IgA in vaginal lavage fluid and specific IgG in serum. This immunisation protocol resulted in enhanced elimination of parasites following intravaginal challenge of BALB/c mice. 相似文献
9.
Medrano LM García-Magariños M Dema B Espino L Maluenda C Polanco I Figueredo MÁ Fernández-Arquero M Núñez C 《PloS one》2012,7(2):e31244
Th17 cells are known to be involved in several autoimmune or inflammatory diseases. In celiac disease (CD), recent studies suggest an implication of those cells in disease pathogenesis. We aimed at studying the role of genes relevant for the Th17 immune response in CD susceptibility. A total of 101 single nucleotide polymorphisms (SNPs), mainly selected to cover most of the variability present in 16 Th17-related genes (IL23R, RORC, IL6R, IL17A, IL17F, CCR6, IL6, JAK2, TNFSF15, IL23A, IL22, STAT3, TBX21, SOCS3, IL12RB1 and IL17RA), were genotyped in 735 CD patients and 549 ethnically matched healthy controls. Case-control comparisons for each SNP and for the haplotypes resulting from the SNPs studied in each gene were performed using chi-square tests. Gene-gene interactions were also evaluated following different methodological approaches. No significant results emerged after performing the appropriate statistical corrections. Our results seem to discard a relevant role of Th17 cells on CD risk. 相似文献
10.
Grazziela P. Figueredo Peer-Olaf Siebers Uwe Aickelin Amanda Whitbrook Jonathan M. Garibaldi 《PloS one》2015,10(3)
Advances in healthcare and in the quality of life significantly increase human life expectancy. With the aging of populations, new un-faced challenges are brought to science. The human body is naturally selected to be well-functioning until the age of reproduction to keep the species alive. However, as the lifespan extends, unseen problems due to the body deterioration emerge. There are several age-related diseases with no appropriate treatment; therefore, the complex aging phenomena needs further understanding. It is known that immunosenescence is highly correlated to the negative effects of aging. In this work we advocate the use of simulation as a tool to assist the understanding of immune aging phenomena. In particular, we are comparing system dynamics modelling and simulation (SDMS) and agent-based modelling and simulation (ABMS) for the case of age-related depletion of naive T cells in the organism.
We address the following research questions: Which simulation approach is more suitable for this problem? Can these approaches be employed interchangeably? Is there any benefit of using one approach compared to the other? Results show that both simulation outcomes closely fit the observed data and existing mathematical model; and the likely contribution of each of the naive T cell repertoire maintenance method can therefore be estimated. The differences observed in the outcomes of both approaches are due to the probabilistic character of ABMS contrasted to SDMS. However, they do not interfere in the overall expected dynamics of the populations. In this case, therefore, they can be employed interchangeably, with SDMS being simpler to implement and taking less computational resources. 相似文献