Karyotype analysis and chromosomal localization by fish of ribosomal DNA, telomeric [(TTAGGG).sub.N] and [(GATA).sub.N] repeats in Haliotis fulgens and H. corrugata (archeogastropoda: haliotidae).ABSTRACT The chromosomes of the blue abalone abalone (ăbəlō`nē), popular name in the United States for a univalve gastropod mollusk of the genus Haliotis, members of which are also called ear shells, or sea ears, as their shape resembles the human ear. Haliotis fulgens and the yellow abalone Haliotis corrugata were analyzed by means of DAPI DAPI 4',6-Diamidino-2-Phenylindole (double stranded DNA staining)
DAPI Days After Panicle Initiation
DAPI Developer Application Programming Interface staining, and fluorescence in situ hybridization Fluorescence in situ hybridization (FISH)
A technique for diagnosing DiGeorge syndrome before birth by analyzing cells obtained by amniocentesis with DNA probes. FISH is about 95% accurate. with 18S-5.8S-28S rDNA, telomeric [(TTAGGG).sub.n] and [(GATA GATA Gold Anti-Trust Action Committee (International Financial Advocacy Organization)
GATA Georgia Academic Team Association
GATA Gülhane Askerý Tip Akademýsý
GATA Get At Their Asses ).sub.n] repeats DNA probes. The diploid diploid /dip·loid/ (dip´loid)
1. having two sets of chromosomes, as normally found in the somatic cells; in humans, the diploid number is 46.
2. an individual or cell having two full sets of homologous chromosomes. chromosome number found was 36 for both California abalone species. However, the karyologic comparison between H. fulgens and H. corrugata indicated that the blue abalone has 8M + 8SM + 2ST, whereas the yellow abalone has 10M + 7SM + IST. The physical location of 18S-5.8S-28S rDNA clusters was found in the terminal region of the long arms of two pairs of submetacentric chromosomes (4, 11 and 2, 4 respectively). Localization Customizing software and documentation for a particular country. It includes the translation of menus and messages into the native spoken language as well as changes in the user interface to accommodate different alphabets and culture. See internationalization and l10n. of heteromorphisms of FISH-rDNA between homologue homologue /ho·mo·logue/ (hom´ah-log)
1. any homologous organ or part.
2. in chemistry, one of a series of compounds distinguished by addition of a CH2 group in successive members. chromosomes and between sister chromatids, and the presence of interstitial hybridization hybridization /hy·brid·iza·tion/ (hi?brid-i-za´shun)
1. crossbreeding; the act or process of producing hybrids.
2. molecular hybridization
3. signals was found in metacentric metacentric /meta·cen·tric/ (-sen´trik) having the centromere near the middle, so that the arms of the replicating chromosome are approximately equal in length.
adj. and onto submetacentric chromosomes. The presence of microsatellites [(TTAGGG).sub.n] and [(GATA).sub.n] was evidenced after FISH treatment by DNA probes. The telomeric sequence occurred at the ends of all mitotic mitotic
pertaining to mitosis.
degree to which a cell population is proliferating; used as an index of tumor aggression. chromosomes in both abalone species, whereas the (GATA)n repetitive sequence was found on chromosomal interstitials zones and at the ends of some chromosomes, this was manifested after FISH on interphase interphase /in·ter·phase/ (in´ter-faz) the interval between two successive cell divisions, during which the chromosomes are not individually distinguishable.
n. nucleus. In addition, this study contributes with new karyologic information of haliotids from California and gives support to the Tethys model about biogeographical bi·o·ge·og·ra·phy
The study of the geographic distribution of organisms.
bio·ge·og origin, from the Mediterranean Sea to the East Pacific Ocean.
KEY WORDS: abalone chromosomes, Haliotis fulgens, Halitosis halitosis (hăl'ĭtō`sĭs), unpleasant odor carried on the breath. It is usually the result of gum disorder, tooth decay, smoking, indulgence in aromatic foods, or a mild digestive upset. corrugata, FISH, rDNA, [(TTAGGG).sub.n], [(GATA).sub.n]
The abalones (Haliotis spp.) constitute a remarkable group of marine gastropods molluscs that are found throughout most of the world, chiefly in temperate and tropical seas (Leighton 2000). In Mexico they are found along the Pacific coast of the Baja California Peninsula where they are commercially exploited because of the high price reached worldwide (Oakes & Ponte 1996). Because of their economical importance several studies on Haliotidae have been carried out, including population genetic analysis, seed production and ecology (Lindberg 1992, Gonzalez & Scoresby 1996, Harem & Burton 2000, Zuniga et al. 2000, Del Rio-Portilla & Gonzalez-Aviles 2001). However, over the past 3 decades, several abalone species have experienced precipitous declines in abundance (Tegner et al. 1989). Overexploitation, pollution, habitat degradation and diseases have probably maximized the decline process (Burton & Tegner 2000).
The native haliotids to the northeastern Pacific Ocean are assigned to eight species, but taxonomic analysis has united two of these as subspecies subspecies, also called race, a genetically distinct geographical subunit of a species. See also classification. of Haliotis kamtschatkana (Geiger & Poppe Poppe is a surname, and may refer to:
This page or section lists people with the surname Poppe. 2000). Attention has been focused on cytogenetics cytogenetics /cy·to·ge·net·ics/ (-je-net´iks) the branch of genetics devoted to cellular constituents concerned in heredity, i.e. chromosomes. , because this field furnishes useful information on taxonomy of the Haliotidae family. According to Geiger & Groves (1999) based on chromosomal data, a model of progressive increase in chromosome number can be postulated, from a diploid number (2n) of 28 chromosomes in Mediterranean species like H. tuberculata (Arai & Wilkins 1986), to 2n = 32 in Indo-Pacific species (Jarayabhand et al. 1998), to the highest number 2n = 36 in North Pacific species (Okumura et al. 1999). This would suggest that H. tuberculata is a relict RELICT. A widow; as A B, relict of C D. species from the ancient Tethys Sea, and that the abalones dispersed eastwards, which is in agreement with the eastward dispersal pattern in the Pacific. In this scenario, the eight species of California abalones would be early representatives of the family. However, karyologic studies on abalones from California have only been performed on the black abalone H. cracherodii (Minkler 1977) and the red abalone H. rufescens (Gallardo-Escarate et al. 2004). The karyologic comparison among California abalones species showed that all species comprised equal chromosome number (2n = 36), although the relationships among chromosome types have not yet been studied.
Fluorescence in situ hybridization (FISH) is a powerful tool for understanding the genomic organization. By visualizing hybridization sites of a specific DNA probe, FISH permits the direct mapping of genes or DNA DNA: see nucleic acid.
or deoxyribonucleic acid
One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. fragments on specific chromosomes and subchromosomal regions. This method has been used only in few studies to examine the chromosomes in the phylum Mollusca. In fact, available karyologic data on the class Gastropoda indicate that more than 300 species have been analyzed cytogenetically, whereas <20 of them have been examined using this kind of techniques (Vitturi et al. 2002). In Haliotidae, no karyologic studies by FISH have been carried out, therefore the chromosomal gene localization in abalones has not been analyzed.
The present paper was organized with the followings objectives: (a) to describe the karyotype of two California abalone species, Haliotis fulgens (Philippi 1845) and Haliotis corrugata (Wood 1828), (b) to examine the localization of 18S-5.8S-28S rDNA by means of FISH, (c) to ascertain the presence of telomeric [(TTAGGG).sub.n] and [(GATA).sub.n] sequences.
MATERIALS AND METHODS
Abalone Collection and Chromosome Preparation
Specimens of blue abalone, Haliotis fulgens and yellow abalone, H. corrugata were collected by diving from a subtidal population in Cedros Island, Baja California, Mexico (28[degrees]03'N; 115[degrees]8'W). The metaphases were obtained from trochophore troch·o·phore
The small, free-swimming, ciliated aquatic larva of various invertebrates, including certain mollusks and annelids.
[Greek trokhos, wheel (from trekhein, larvae Larvae, in Roman religion
Larvae: see lemures. and the chromosome preparation was performed according to Gallardo-Escarate et al. (2004). The slides were washed in three changes of Phosphate Buffer Saline (1 x PBS PBS
in full Public Broadcasting Service
Private, nonprofit U.S. corporation of public television stations. PBS provides its member stations, which are supported by public funds and private contributions rather than by commercials, with educational, cultural, ) for 5 min each time, and incubated with DAPI solution in the dark for 25 min at room temperature (25[degrees]C) using a Coplin jar. DAPI solution stain was prepared with 4,6-diamidino-2-phenylindole (DAPI) (Sigma-Aldrich, USA) in 1 x PBS at 0.5 [micro]g/mL.
A laboratory test used to study an individual's chromosome make-up. Chromosomes are separated from cells, stained, and arranged in order from largest to smallest so that their number and structure can be studied under a microscope. by Image Analysis
Chromosome spreads were karyotyped from fluorescent digital images. The best metaphases were captured using a motorized mo·tor·ize
tr.v. mo·tor·ized, mo·tor·iz·ing, mo·tor·iz·es
1. To equip with a motor.
2. To supply with motor-driven vehicles.
3. To provide with automobiles. epifluorescent microscope (Leica model DMRXA2) equipped with a RGB color digital camera of 36-bits and 3.3 mega pixels (Leica model DC300). For identification of homologue chromosomes, arm lengths (short and long) were measured with an Image ProPlus software version 4.0 (Copyright 1993-1998 Media Cybernetics cybernetics [Gr.,=steersman], term coined by American mathematician Norbert Wiener to refer to the general analysis of control systems and communication systems in living organisms and machines. ). Measurements were used to determine relative lengths of chromosomes (length of the chromosome pair / total complement length x 100) and centromeric cen·tro·mere
The most condensed and constricted region of a chromosome, to which the spindle fiber is attached during mitosis.
cen index (length of short arm / total length of the chromosome x 100) of each chromosome. To perform a quantitative analysis Quantitative Analysis
A security analysis that uses financial information derived from company annual reports and income statements to evaluate an investment decision.
Notes: between H. fulgens and H. corrugata a karyoideogram was plotted according to Spotorno (1985).
Fluorescence In situ Hybridization
To decrease unspecific Adj. 1. unspecific - not detailed or specific; "a broad rule"; "the broad outlines of the plan"; "felt an unspecific dread"
general - applying to all or most members of a category or group; "the general public"; "general assistance"; "a general rule"; hybridizations, slides were pretreated with 100 [micro]g/mL RNAse in 2xSSC (pH 7.0) buffer at 37[degrees]C for l h and then washed twice for 5 min each in 2 x SSC SSC Secondary School Certificate
SSC Standard Systems Center (USAF)
SSC State Services Commission (New Zealand)
SSC Swedish Space Corporation
SSC Salem State College (Massachusetts) at RT and one time at 37[degrees]C for 5 min. Then the slides were incubated in 5 [micro]g/mL pepsin pepsin, enzyme produced in the mucosal lining of the stomach that acts to degrade protein. Pepsin is one of three principal protein-degrading, or proteolytic, enzymes in the digestive system, the other two being chymotrypsin and trypsin. in 0.01 M HCl for 10 min at 37[degrees]C. After the treatment the slides were washed two times for 5 min each in 1 x PBS, fixed in 1% formaldehyde for 10 min at RT, washed twice for 5 min each in 1 x PBS, rinsed in 0.85% NaCl and dehydrated de·hy·drate
v. de·hy·drat·ed, de·hy·drat·ing, de·hy·drates
1. To remove water from; make anhydrous.
2. To preserve by removing water from (vegetables, for example). in a series of ethanol concentrations (30%, 50%, 70%, 90% and 100%). Finally, slides were air dried and stored at -80[degrees]C.
The chromosomal localization of the major rDNA gene cluster was performed using a probe containing 18S-5.8S-28S genes plus intergenic spacer of D. melanogaster (pDm238) (Roiha et al. 1981) and cloned in pBR322 plasmid of E. coli (strain JM109). The plasmid purification was performed with a NucleoSpin Plasmid kit (Macherey-Nagel) and it was labeled with Dig-Nick Translation Mix kit (Roche Molecular Biochemicals) according to manufacturer's instructions. After obtaining the labeled probe, the hybridization mixture was added onto pretreated chromosome preparations and heated to 72[degrees]C for 7 min to denature de·na·ture
1. To change the nature or natural qualities of.
2. To render unfit to eat or drink without destroying usefulness in other applications, especially adding methyl alcohol to ethyl alcohol.
3. DNA. In situ hybridization in situ hybridization A method for localizing a sequence of DNA, mRNA, or protein in a cell or tissue; the use of a DNA or RNA probe to detect a cDNA sequence in chromosome spreads or in interphase nuclei or an RNA sequence of cloned bacterial or cultured was allowed to proceed at 37[degrees]C overnight, followed by posthybridization washes, three times for 5 min each in 50% formamide in 2 x SSC at 44[degrees]C, three times for 5 min each in 0.1 x SSC at 60[degrees]C, 5 min in 2 x SSC at RT, 5 min in TNT TNT: see trinitrotoluene.
in full trinitrotoluene
Pale yellow, solid organic compound made by adding nitrate (−NO2) groups to toluene. at RT and 30 min in TNB TNB Tenaga Nasional Berhad (electric power utility in Malaysia)
TNB Tacoma Narrows Bridge
TNB Thomas and Betts
TNB Télévision Nationale du Burkina (Burkina Faso) at RT.
FISH with telomeric [(TTAGGG).sub.n] and [(GATA).sub.n]. DNA probes were amplified by PCR PCR polymerase chain reaction.
polymerase chain reaction
Polymerase chain reaction (PCR) in volumes of 50 [micro]L of the reaction mixture in absence of template using (TTAGGG).sub.5] and [(CCCTAA).sub.5] and [(GATA).sub.7] and [(TATC TATC Transportation Appeal Tribunal of Canada
TATC Tea Association Technical Committee
TATC Tactical/Terminal Air Traffic Control
TATC Trainee Air Traffic Controller (UK)
TATC Tactical Aeromedical Training Course ).sub.7] as primers, respectively (Ijdo et al. 1991). The PCR conditions were performed by 10 cycles at 94[degrees]C for 1 min, 55[degrees]C for 30 sec, 72[degrees]C for 1 min and 30 standard PCR amplification cycles at an annealing annealing (ənēl`ĭng), process in which glass, metals, and other materials are treated to render them less brittle and more workable. temperature of 60[degrees]C. Nick translation labeling with digoxigenine was performed and in situ hybridization was carried out as mentioned earlier and followed by posthybridization washes at 42[degrees]C (telomeric probe) or 37[degrees]C (GATA probe). For detection of hybridization, chromosomes were incubated in 0.5 [micro]g/mL mouse antidigoxigenine and detected in 0.2 [micro]g/mL Rabbit antiMouse FITC-conjugated, and finally in FITC-conjugated Goat antiRabbit at a concentration of 0.1 [micro]g/mL. Chromosome slides were counterstained and mounted with 30 [micro]L of IP-V 500 ng/mL (propidium iodide plus Vectashield antifading medium). Fluorescence images of FISH were obtained by using an epifluorescence microscope (Axioskop 2 plus, Zeiss) and recorded by a cooled CCD camera (CoolSnap, Photometrics Inc.).
Karyotype of H. fulgens
Metaphase metaphase /meta·phase/ (met´ah-faz) the second stage of cell division (mitosis or meiosis), in which the chromosomes, each consisting of two chromatids, are arranged in the equatorial plane of the spindle prior to separation. chromosomes of the blue abalone H. fulgens, showed a diploid number equal to 36 chromosomes. The mean values and standard deviations of the total lengths, relative lengths and centromeric index were estimated from chromosome arm lengths using image analysis (Table 1). The maximum length of chromosomes was 6.07 [+ or -] 0.12 [micro]m and the minimum was 3.13 [+ or -] 0.21 [micro]m. The ratio of the chromosome arms plotted in the karyoideogram indicated that this species possess 8 metacentric pairs (1, 3, 6, 9, 10, 16, 17 and 18), 8 submetacentric pairs (2, 4, 5, 7, 8, 11, 12 and 13), and 2 pairs of subtelocentric chromosomes (14 and 15). The distribution of relative chromosome lengths was derived to perform a karyotypic arrangement (8M + 8SM + 2ST) (Fig. 1).
[FIGURE 1 OMITTED]
In situ Hybridization in H. fulgens
FISH using a probe derived from 18S-5.8S-28S rDNA genes produced strong signals on the telomere telomere /telo·mere/ (tel´o-mer) an extremity of a chromosome, which has specific properties, one of which is a polarity that prevents reunion with any fragment after a chromosome has been broken. of the long arms of 2 pairs of submetacentric chromosomes (pairs 4 and 11). Metaphase chromosomes from larvae showed heteromorphisms of NORs between sister chromatids and low interstitial signals were mainly found in submetacentric chromosomes. However, the specific localization of regions with low signal intensity showed a high cytogenetic cytogenetic /cy·to·ge·net·ic/ (-je-net´ik)
1. pertaining to chromosomes.
2. pertaining to cytogenetics.
pertaining to or originating from the origin and development of the cell. variability in all metaphases analyzed (Fig. 2a and 2b).
[FIGURE 2 OMITTED]
After FISH treatment with the telomeric sequence [(TTAGGG).sub.n], abalone's chromosomes were found positive to telomeric probe. Strong signals were found at the ends of all chromosome types analyzed (Fig. 2c). The visualization of the interphase nucleus labeled with the telomeric probe allowed to evidence the distribution of telomeres in clusters at the nuclear periphery (Fig. 2d). The presence of the (GATA), microsatellite See miniaturized satellite. on chromosomes of H. fulgens was found positive for the signal of hybridization (Fig. 2e). The localization of these regions was found in chromosomal interstitial zones and at the ends of some chromosomes, this was manifested after FISH treatment on interphase nuclei (Fig. 2f).
Karyotype of H. corrugata
Metaphases examined in the yellow abalone H. corrugata, showed a chromosome number of 2n = 36. By arranging into chromosome pairs, the karyotype consisted of 10 metacentric pairs (1, 3, 6, 9, 10, 11, 14, 15, 17 and 18), 7 submetacentric pairs (2, 4, 5, 7, 8, 12 and 13), and 1 pair of subtelocentric chromosomes (16). Chromosome pair 10 showed overlapping between metacentric and submetacentric types (Fig. 3). According to chromosome total lengths, relative lengths and centromeric index, the maximum chromosome length was 5.82 [+ or -]0.12 [micro]m and the minimum was 3.46 [+ or -] 0.05 [micro]m (Table 2).
[FIGURE 3 OMITTED]
In situ hybridization in H. corrugata
Strong signals on the telomere of the long arms of 2 pairs of submetacentric chromosome (2 and 4) were produced by NORs with FISH treatment. Heteromorphisms of NORs were found between sister chromatids. Presence of interstitial regions was found in metacentric and in submetacentric chromosomes. The localization of low hybridization signals showed high variability (Fig. 4a, 4b).
[FIGURE 4 OMITTED]
Telomeric [(TTAGGG).sub.n] DNA probe showed positive hybridization in chromosomes of yellow abalone and strong signals were found (Fig. 4c). FISH onto interphase nucleus showed a peripheral distribution of the telomeres at the nuclear periphery (Fig. 4d). The presence of [(GATA).sub.n] sequence was corroborated cor·rob·o·rate
tr.v. cor·rob·o·rat·ed, cor·rob·o·rat·ing, cor·rob·o·rates
To strengthen or support with other evidence; make more certain. See Synonyms at confirm. in H. corrugata chromosomes (Fig. 4e). The localization of these regions was also variable (Fig. 4f).
The genus Haliotis is a complex and diverse group of archaeogastropods related by an economical importance and inconclusive systematics systematics: see classification. . In this sense, several studies have been carried out to approach the genetic characteristics of abalones throughout the world (Lee & Vacquier 1995, Elliott 2000). Cytogenetic analyses such as chromosome number and morphology are useful to trace phylogenetic phy·lo·ge·net·ic
1. Of or relating to phylogeny or phylogenetics.
2. Relating to or based on evolutionary development or history. patterns and evolutionary relationships. Karyologic data in abalone species show a variation of diploid number from 28-36 chromosomes (Jarayabhand et al. 1998). The review of karyotypes reported in abalones and their geographic distribution (Geiger & Poppe 2000), showed that abalones from the European Mediterranean region have a 2n = 28. Representative abalones from the Indo-Pacific region have a characteristic 2n = 32, with the exception of H. aquatilis with a diploid number equal to 34 chromosomes. The abalones found in the South Japan region show a 2n = 32. Finally, abalones from the North Pacific or Japanese abalones have a diploid chromosome number of 36. In reference to karyologic data from species belonging to the North Oriental Pacific and specially from California, only the karyotypes of the black abalone H. cracherodii (Minkler 1977) and recently of the red abalone H. rufescens (Gallardo-Escarate et al. 2004) have been reported. Both abalone species showed a chromosome number of 2n = 36. The increase in diploid chromosome number suggests that abalones from the European Mediterranean region are relict species from the ancient Tethys Sea, and those abalones were dispersed eastwards, which is in agreement with the eastward dispersal pattern in the Pacific. In this scenario, the California abalone species would be more recent haliotids.
This study is the first karyologic report of the blue abalone Haliotisfulgens and the yellow abalone H. corrugata. Our results showed that a 2n = 36 chromosomes was observed in both abalone species. This result confirms a characteristic diploid number for abalone species from California. However, the karyologic comparison between H. fulgens and H. corrugata indicate that the blue abalone has 8M + 8SM + 2ST, whereas the yellow abalone has 10M + 7SM + IST (Fig. 5). In addition, H. rufescens and H. cracherodii described for this region showed that these species are similar in the metacentric chromosome number equal to eight pairs (8M). The differences are that the red abalone has 9SM + 1ST, whereas the black abalone has 8SM + 2ST. According to Patterson (1969) basal gastropods have a low diploid number of chromosomes, whereas recent gastropods species frequently exhibit higher chromosome numbers. Parallel to the increase of chromosome number, in certain aquatic organisms often an enlargement of submetacentric and telocentric chromosomes is observed, probably by chromosomal fission fission, in physics: see nuclear energy and nucleus; see also atomic bomb. (Thiriot-Quievreux 1994).
[FIGURE 5 OMITTED]
The karyologic conformation of H. fulgens and H. corrugata suggests a deletion process of the short arms in some submetacentric chromosome pairs, originating subtelocentric pairs. In this scenario, it is possible to suggest that H. fulgens is an abalone species with considerable chromosomal loss and rearrangements in comparison with H. corrugata. Furthermore, the highest number of metacentric chromosomes of the yellow abalone suggests that this species is the most ancestral among the California abalones karyologically reported. Phylogenetic relationships studied by Lee & Vacquier (1995), and Coleman & Vacquier (2002) among California species, showed that H. corrugata was phylogenetically phy·lo·ge·net·ic
1. Of or relating to phylogeny or phylogenetics.
2. Relating to or based on evolutionary development or history: a phylogenetic classification of species. closer to Japanese abalone species in comparison with other species like H. rufescens, whereas H. fulgens appears as the genetically most distant species or the most recent, compared with the other California abalones.
Fluorescence in situ hybridization is a powerful technique used to characterize and to detect DNA segments in chromosomes. This method of molecular cytogenetics allows the physical location of genes independently of their transcription activity. Although the FISH technique has been extensively used in many animal and plant species, in molluscs it has mainly been applied in bivalves (Zhang et al. 1999, Vitturi et al. 2000b, Insua et al. 2001, Martinez et al. 2002, Cross et al. 2003). In reference to gastropods, less than 20 of 300 species analyzed cytogenetically have been examined by FISH (Vitturi et al. 2002).
The ribosomal RNA genes are a group of DNA sequences that produce structural RNA RNA: see nucleic acid.
in full ribonucleic acid
One of the two main types of nucleic acid (the other being DNA), which functions in cellular protein synthesis in all living cells and replaces DNA as the carrier of genetic to support protein synthesis. The nucleotide sequences of these genes are often polymorphic, which has enabled taxonomic investigation of organisms with ambiguous phylogenetic relationships (Littlewood 1994). Furthermore, rDNA sequences are useful for the initiation of physical genome mapping, because the gene exists in multiple copies, which improves its detection. According to our results, the 18S-5.8S-28S rDNA of H. fulgens and H. corrugata was localized by FISH at the ends of two pairs of submetacentric chromosomes (4, 11 and 2, 4 respectively). To our knowledge, in abalone only one study has been reported in reference to location of the nucleolar nucleolar
pertaining to or emanating from nucleolus. organizing region (NOR). According to Okumura et al. (1999), variations in NOR-bearing chromosomes were observed in H. discus hannai and located terminally on the long arms of two chromosome pairs. However, these NORs were visualized by silver nitrate staining (AgNOR staining) and therefore any NORs in the nonactive state remained undetected. Our results showed localization of heteromorphisms of FISH-rDNA between homologues and between sister chromatids, and presence of interstitial hybridization signals were found in metacentric as well as onto submetacentric chromosomes. These results may indicate that the copy number variability of rDNA and mistakes are caused by either deleting or duplicating rDNA clusters during the DNA replication. This FISH-rDNA variability is in agreement with other studies reported in molluscs (Martinez-Exposito et al. 1997, Torreiro et al. 1999, Insua et al. 2001, Martinez et al. 2002, Cross et al. 2003).
In this study, we used in addition to the rDNA FISH, in situ hybridization with [(TTAGGG).sub.n] and [(GATA).sub.n] probes to test for the presence of these sequences in H. fulgens and H. corrugata chromosomes. The results demonstrated that the telomeric sequence occurred at the ends of all mitotic chromosomes in abalones. In molluscs, conservation of the telomeric region has been reported in bivalves (Guo & Allen 1997) and gastropods (Vitturi et al. 2002), and therefore the telomere repeat is widespread within the Phylum phylum, in taxonomy: see classification. .
The genome of blue and yellow abalones, revealed evident hybridization sites by the [(GATA).sub.n] FISH. In fact, this result was according to that reported in other gastropods species (Vitturi et al. 2000a, Colomba et al. 2002), in reference to the [(GATA).sub.n] microsatellite occurring among Mollusk mollusk: see Mollusca.
Any of some 75,000 species of soft-bodied invertebrate animals (phylum Mollusca), many of which are wholly or partly enclosed in a calcium carbonate shell secreted by the mantle, a soft taxa taxa: see taxon. . Other studies have shown a heterogeneous distribution of the sequence that was found to be absent or, if present, occurred in a low amount (Vitturi et al. 2002). In conclusion, studies by FISH performed in molluscs are useful to examine the genomic constitution at the molecular level and for the reconstruction of chromosomal changes during evolution. In this context, rDNA probes have been used to examine the Robertsonian process in Nucella lapillus la·pil·lus
n. pl. la·pil·li
A small, solidified fragment of lava.
[Latin, diminutive of lapis, stone. (Pascoe et al. 1996). In addition, the use of the microsatellite [(GATA).sub.n] revealed that this sequence does not occur in the Y chromosome of the neogastropod Fasciolaria lignaria (Vitturi et al. 2000a). Therefore this sequence could be used to test sex-linked arrangements in abalone species.
The authors thank Jose Guadalupe Gonzalez and SCPP SCPP Self-Consistent Polarization Propagator Pescadores Nacionales de Abulon for the logistic support in abalone collection and spawning procedure. This study was supported by CONACYT CONACYT Consejo Nacional de Ciencia y Tecnología (National Board of Science and Technology; Mexico, Bolivia, Paraguay) (Mexico) project 36075-B and Project 33018-B, project OPAM OPAM Object Perception, Attention and Memory
OPAM Office of Procurement and Assistance Management (US DOE)
OPAM Opera di Promozione per l'Alfabetizzazione nel Mondo
OPAM On-Premise Account Managers
OPAM Optical Parallel Architecture Model from the INTERREG IIIA IIIA Internet Information Infrastructure Architecture
IIIA Integrated Intelligence Information Application
IIIA International Imaging Industry Association (EEC EEC: see European Economic Community. ) and project CVI CVI C (Language) Virtual Instrument
CVI Clinical and Vaccine Immunology (journal)
CVI Chronic Venous Insufficiency
CVI Coastal Vulnerability Index
CVI Canaan Valley Institute 219 from the Junta de Andalucia (Spain). The first author is a CONICYT-BID (Chile) Ph.D. fellow. The first author thanks Direccion de Telematica for the support received in the writing of this paper.
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periwinkle, any of a group of marine gastropod mollusks having conical, spiral shells. Periwinkles feed on algae and seaweed. Melarhaphe neritoides (Prosobranchia, Gastropoda, Caenogastropoda). Heredity 88: 381-384.
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CRISTIAN GALLARDO-ESCARATE, (1,2) * JOSUE ALVAREZ-BORREGO, (2) MIGUEL ANGEL DEL RIO-PORTILLA, (3) ELISABETH VON BRAND-SKOPNIK, (1) ISMAEL CROSS, (4) ALEJANDRO MERLO (4) AND LAUREANA REBORDINOS (4)
(1) Departamento de Biologia Marina, Facultad de Ciencias del Mar, Universiclad Catolica del Notre. Larrondo 1281, Casilla 117, Coquimbo. Chile; 2Direcci6n de Telematica, (3) Departamento de Acuicultura, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada. Km. 107 Carretera Tijuana-Ensenada, Codigo Postal 22860. Ensenada, B.C. Mexico. (4) Laboratorio de Genetica, Facultad de Ciencias del Mar, Universidad de Cadiz., 11510 Puerto Real. Cadiz, Espana.
* Corresponding author: email@example.com
TABLE 1. Total chromosome lengths, relative length and centromeric index for Haliotis fulgens (2n = 36). Total Relative Chromosome Length (km) Length(%) Pair No. (Mean [+ or - std) (Mean [+ or - std) 1 6.07 [+ or -] 0.12 8.00 [+ or -] 0.27 2 5.06 [+ or -] 0.81 6.67 [+ or -] 0.12 3 4.84 [+ or -] 0.11 6.37 [+ or -] 0.38 4 4.72 [+ or -] 0.68 6.23 [+ or -] 0.49 5 4.16 [+ or -] 0.93 5.48 [+ or -] 0.22 6 4.62 [+ or -] 0.35 6.08 [+ or -] 0.12 7 4.56 [+ or -] 0.68 6.01 [+ or -] 0.07 8 4.41 [+ or -] 0.79 5.82 [+ or -] 0.40 9 4.24 [+ or -] 0.49 5.59 [+ or -] 0.20 10 4.14 [+ or -] 0.36 5.45 [+ or -] 0.10 11 4.04 [+ or -] 0.69 5.32 [+ or -] 0.20 12 3.98 [+ or -] 0.87 5.24 [+ or -] 0.26 13 3.81 [+ or -] 0.51 5.02 [+ or -] 0.31 14 3.86 [+ or -] 1.38 5.09 [+ or -] 0.21 15 3.63 [+ or -] 1.29 4.78 [+ or -] 0.25 16 3.50 [+ or -] 0.25 4.61 [+ or -] 0.19 17 3.13 [+ or -] 0.08 4.13 [+ or -] 0.23 18 3.13 [+ or -] 0.21 4.13 [+ or -] 0.22 Centromeric Chromosome Index Chromosome Pair No. (Mean [+ or -] std) Type * 1 47.45 [+ or -] 0.16 M 2 34.09 [+ or -] 0.15 SM 3 48.37 [+ or -] 0.17 M 4 39.81 [+ or -] 0.18 SM 5 34.16 [+ or -] 0.14 SM 6 44.69 [+ or -] 0.13 M 7 39.41 [+ or -] 0.10 SM 8 37.27 [+ or -] 0.17 SM 9 42.74 [+ or -] 0.15 M 10 43.77 [+ or -] 0.12 M 11 37.98 [+ or -] 0.15 SM 12 34.51 [+ or -] 0.09 SM 13 40.59 [+ or -] 0.15 SM 14 24.73 [+ or -] 0.14 ST 15 24.82 [+ or -] 0.17 ST 16 44.97 [+ or -] 0.12 M 17 48.29 [+ or -] 0.20 M 18 45.20 [+ or -] 0.09 M * M, metacentric; SM, submetacentric; ST, subtelocentric. TABLE 2. Total chromosome lengths, relative length and centromeric index for Haliotis corrugata (2n = 36). Total Relative Chromosome Length (pm) Length(%) Pair No. (Mean [+ or -] std) (Mean [+ or -] std) 1 5.82 [+ or -] 0.12 7.28 [+ or -] 0.27 2 5.00 [+ or -] 0.08 6.26 [+ or -] 0.12 3 4.82 [+ or -] 0.03 6.03 [+ or -] 0.38 4 4.80 [+ or -] 0.06 6.00 [+ or -] 0.49 5 4.59 [+ or -] 0.02 5.74 [+ or -] 0.22 6 4.53 [+ or -] 0.06 5.66 [+ or -] 0.12 7 4.52 [+ or -] 0.05 5.66 [+ or -] 0.07 8 4.45 [+ or -] 0.02 5.57 [+ or -] 0.40 9 4.44 [+ or -] 0.04 5.55 [+ or -] 0.20 10 4.34 [+ or -] 0.01 5.43 [+ or -] 0.10 11 4.32 [+ or -] 0.08 5.40 [+ or -] 0.20 12 4.29 [+ or -] 0.02 5.36 [+ or -] 0.26 13 4.24 [+ or -] 0.02 5.30 [+ or -] 0.31 14 4.22 [+ or -] 0.09 5.28 [+ or -] 0.21 15 4.07 [+ or -] 0.03 5.09 [+ or -] 0.25 16 4.03 [+ or -] 0.02 5.04 [+ or -] 0.19 17 4.01 [+ or -] 0.01 5.02 [+ or -] 0.23 18 3.46 [+ or -] 0.05 4.32 [+ or -] 0.22 Centromeric Chromosome Chromosome Index Type * Pair No. (Mean [+ or -] std) 1 48.02 [+ or -] 0.06 M 2 35.90 [+ or -] 0.11 SM 3 46.70 [+ or -] 0.05 M 4 39.95 [+ or -] 0.08 SM 5 36.93 [+ or -] 0.06 SM 6 43.81 [+ or -] 0.09 M 7 34.51 [+ or -] 0.09 SM 8 36.91 [+ or -] 0.08 SM 9 49.16 [+ or -] 0.07 M 10 41.09 [+ or -] 0.07 M 11 47.98 [+ or -] 0.16 M 12 37.38 [+ or -] 0.04 SM 13 34.82 [+ or -] 0.08 SM 14 44.74 [+ or -] 0.10 M 15 47.04 [+ or -] 0.03 M 16 22.44 [+ or -] 0.04 ST 17 48.59 [+ or -] 0.02 M 18 45.50 [+ or -] 0.07 M * M. metacentric: SM. submetacentric: ST. subtelocentric.