Development and mapping of microsatellites from a microdissected BTA 11-specific DNA library

A chromosome-specific library was developed for Bos taurus autosome 11 by chromosome microdissection and microcloning using a bovine primary fibroblast culture, obtained from a t(X;23) heifer, that spontaneously developed a translocation chromosome involving bovine chromosome 11. The library was screened using (AC)12 oligos, positive clones selected, sequenced and primers developed to generate bovine chromosome 11-specific microsatellite markers. This study suggests that chromosome-specific libraries have great potential for development of microsatellite markers for the construction of marker-saturated linkage maps for each chromosome.     

Comparative analysis of polymorphism and chromosomal location of tomato microsatellite markers isolated from different sources

Previously isolated tomato (Lycopersicon esculentum) microsatellite markers were mainly clustered in the centromeric heterochromatin and not located in euchromatic regions. To achieve a more-uniform distribution of microsatellite markers for genome mapping purposes, a set of tomato microsatellite markers containing dinucleotide simple sequence repeats were developed by screening genomic libraries enriched for single-copy sequences, and screening the tomato EST database. The tomato microsatellites isolated in these ways were characterized by combinations of different types of repeated motifs and they were polymorphic in a set of L. esculentum varieties detecting up to four alleles. A total of 20 markers were placed on the genetic map of tomato. Interestingly, all markers isolated from genomic libraries enriched for single-copy sequences by PstI-pre-digestion mapped into the centromeric regions. The majority of markers derived from EST sequences contained predominantly AT microsatellites and were located in euchromatic regions. Received: 22 December 2000 / Accepted: 4 May 2001     

Mapping of 55 new rat microsatellite markers from chromosome-specific libraries

Fifty-five novel rat microsatellite markers were isolated from libraries specific for rat chromosomes (Chrs) 1, 2, and 7. The markers were mapped in three backcross rat populations. Thirty of these markers mapped to Chrs 1, 2, or 7, while the other 25 mapped to other chromosomes. New markers for two genes, liver-specific transporter gene (Livtr) and insulin-responsive glucose transporter (Glut4), were also mapped to rat Chrs 9 and 10, respectively. Three provisionally assigned markers from previous studies were also confirmed. Detailed methodologies for the generation and enrichment of clones containing repeat sequences and for the isolation of chromosome-specific markers are presented, since they represent unique combinations and modifications of previous protocols. Such methods and the newly presented markers should be useful for both specific and general mapping studies in the rat. Received: 11 February 1998 / Accepted: 7 April 1998     

Development and evaluation of microsatellite markers in Phoenix dactylifera L. and their transferability to other Phoenix species

Forty one simple sequence repeats were isolated from two microsatellite enriched libraries of date palm (Phoenix dactylifera L.). After screening, 17 selected microsatellite loci were characterized and evaluated on a set of 31 cultivars and clones from Algerian and Californian germplasm. All primer pairs produced an amplification product of the expected size and detected high polymorphism among the analysed samples. These nuclear simple sequence repeat (SSR) markers are expected to be a very effective tool for evaluating genetic diversity in date palm germplasm. Acrosstaxa amplification showed the usefulness of most SSR markers in 14 other species across the genus Phoenix.     

Isolation and characterization of nine microsatellite loci for the takin (<Emphasis Type="Italic">Budorcas taxicolor</Emphasis>)

We report on the isolation and characterization of nine microsatellite markers in the takin (Budorcas taxicolor) from genomic DNA-enriched libraries. Twenty-eight microsatellites were screened from the libraries, and nine of the screened microsatellites were polymorphic. The number of observed alleles for each locus in 28 individuals ranged from two to seven, and the expected and observed heterozygosity was 0.105–0.758 and 0.071–0.821, respectively. Four loci (TK01, TK02, TK04 and TK08) of nine deviated from Hardy-Weinberg expectation and no significant linkage association was found among all these loci. These microsatellite markers provide useful tool for population genetic studies of the takin.     

A Mouse Chromosome-Specific YAC Probe Collection forin SituHybridization

To facilitate the identification of mouse metaphase chromosomes by fluorescencein situhybridization (FISH), a complete collection of mouse chromosome-specific markers has been established. Yeast artificial chromosome libraries were screened by polymerase chain reaction using primers for known loci. DNAs from positive clones were then tested by FISH. One probe per chromosome was selected on the basis of high specificity (nonchimerism) and strong fluorescence.     

Isolation and characterization of eight polymorphic microsatellite loci for the critically endangered Arenaria nevadensis (Caryophyllaceae)

We report on the isolation and characterization of eight microsatellite markers from enriched libraries for Arenaria nevadensis, one of the most critically endangered plant species in the Iberian Peninsula. These are the first microsatellite loci reported for Arenaria species. The number of alleles ranged from two to eight, and the expected heterozygosity from 0.067 to 0.873. These markers will be useful for characterizing the genetic diversity in A. nevadensis and understanding its population structure, and will provide important genetic data for the conservation and recovery of this species.     

Isolation and characterization of microsatellite loci in <Emphasis Type="Italic">Cryptocarya chinensis</Emphasis> in lower subtropical China

We report on the isolation and characterization of eight microsatellite markers from repetitive DNA enriched libraries for Cryptocarya chinensis from lower subtropical China. These are the first microsatellite loci reported for Cryptocarya species. The number of alleles ranged from three to nine. Observed and expected heterozygosities ranged from 0.0518 to 0.9910 and 0.5241 to 0.7935 for polymorphic loci, respectively. These markers will allow analyses of the baseline genetic variability and population structure of C. chinensis to enrich our scientific understanding of forest fragmentation on genetic health of this species and provide strategies for effective conservation and management in this area.     

Isolation and characterization of eight microsatellite loci for the vulnerable Hainan Eld’s deer (<Emphasis Type="Italic">Cervus eldi hainanus</Emphasis>) in China

We report on the isolation and characterization of eight microsatellite markers in the Hainan Eld’s deer (Cervus eldi hainanus) from genomic DNA-enriched libraries. Thirty-three microsatellites were screened from the libraries, and 8 of the screened microsatellites were polymorphic. The number of observed alleles for each locus in 47 individuals ranged from 2 to 9, and the expected and observed heterozygosity was 0.141–0.792 and 0.128–0.957, respectively. Three loci (CEH-2, CEH-6 and CEH-8) of eight deviated from Hardy-Weinberg expectation and no significant linkage association was found among all these loci. These microsatellite markers provide useful tool for population genetic studies of the Eld’s deer.     

Six new polymorphic microsatellite loci isolated and characterized from the African savannah elephant genome

The African savannah elephant (Loxodonta africana) is a ‘keystone’ species that plays a vital role in regulating the dynamics of both plant and animal communities and yet it is endangered and its numbers have been reduced to approximately 500 000 across their entire continental range. Molecular genetic markers are important tools for providing genetic information useful in formulating effective management and conservation strategies for the surviving elephant populations. We describe the isolation and characterization of six new polymorphic microsatellite markers in the African savannah elephant and demonstrate that these loci can be PCR (polymerase chain reaction)‐multiplexed, a desirable attribute that saves costs in large‐scale microsatellite screening.     

Development of microsatellite markers in potato and their transferability in some members of Solanaceae

We have developed thirty new microsatellite markers in potato by screening genomic libraries and ESTs. Genomic libraries of potato cultivar Kufri Bahar were screened for sequences containing microsatellite motifs GA, GT, ACA, ATC, GAA, TAA and GATA. Using flanking sequences, PCR primers were designed for microsatellites identified from genomic libraries and ESTs. Sixteen new primer pairs from genomic libraries and fourteen from ESTs along with seven previously published primer pairs amplified PCR products in the selected genotypes comprising of 65 Solanum tuberosum lines and 14 other species of the potato gene pool. Neighbor-joining tree based on genetic distance matrix developed using microsatellite markers successfully distinguished all these genotypes in the expected size range. Seventeen microsatellites could also be cross-amplified in at least one of the five members of solanaceae, namely tomato, eggplant, pepper, petunia and tobacco. The new microsatellite markers obtained in this study will be useful in various genetic and taxonomic studies in potato and related genomes.     

Development of microsatellite markers for the endangered freshwater pearl mussel Margaritifera margaritifera L. (Bivalvia: Unionoidea)

Freshwater pearl mussels (Margaritifera margaritifera L.) are among the most critically endangered freshwater invertebrates. We describe the isolation and characterization of the first microsatellite markers for this species, which were obtained by screening 4900 recombinant clones from two genomic libraries. Thirteen loci revealed polymorphisms as demonstrated on 42 tested individuals from four river drainages. Allelic richness ranged from two to 12 alleles and averaged 6.8 alleles per locus with heterozygosity levels varying from 0 to 0.850 for observed heterozygosity (H_O) and from 0.174 to 0.850 for expected heterozygosity (H_E). Deficiency of heterozygous genotypes was observed in eight of 13 loci.     

Isolation and characterization of 149 novel microsatellite DNA markers for striped bass,Morone saxatilis,and cross‐species amplification in white bass,Morone chrysops,and their hybrid

To support detailed genetic analysis of striped bass (Morone saxatilis) and white bass (Morone chrysops), we isolated 153 microsatellite loci from repeat‐enriched striped bass DNA libraries. Of these, 147 markers amplified in striped bass (average 4.7 alleles per locus) and 133 in white bass (average 2.2 alleles per locus). One hundred twenty‐two markers amplified in their hybrid. Development of new microsatellite markers will facilitate evaluations of genetic structure in wild populations and will support pedigree analysis and linkage mapping for selective breeding.     

Isolation and characterization of microsatellites loci in the lemon (Citrus limon)

This study reports the isolation and characterization of seven polymorphic microsatellite loci in Citrus. The loci were isolated from two libraries constructed from genomic DNA nonenriched for TC and AC repeats and enriched for AC repeats. These markers yielded four to nine alleles per locus (mean 6.14) in a survey of 32 Citrus cultivars. Average observed heterozygosity ranged from 0.43 to 0.72. The levels of polymorphism found in this study suggest that these microsatellite loci can become an important tool for genetic studies in Citrus.     

Isolation and characterization of first microsatellite markers for the noble crayfish, <Emphasis Type="Italic">Astacus astacus</Emphasis>

Noble crayfish (Astacus astacus) is listed as vulnerable by the IUCN Red List of Threatened Species in Europe. However, very little is known about genetic diversity and structuring of noble crayfish populations, mainly because of the lack of informative genetic markers. We describe the isolation and characterization of the first microsatellite markers for this species, which were obtained by screening 4,000 recombinant clones. Eight loci revealed polymorphisms in a panel of 172 individuals from seven populations in Northern Europe. Number of alleles per locus ranged from two to 10 (average 4.4) and heterozygosity levels among populations varied from 0 to 0.80 for H _o and from 0 to 0.72 for H _e.     

Dissection of the nuclear genome of barley by chromosome flow sorting

Isolation of mitotic chromosomes using flow cytometry is an attractive way to dissect nuclear genomes into their individual chromosomal components or portions of them. This approach is especially useful in plants with complex genomes, where it offers a targeted and hence economical approach to genome analysis and gene cloning. In several plant species, DNA of flow-sorted chromosomes has been used for isolation of molecular markers from specific genome regions, for physical mapping using polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH), for integration of genetic and physical maps and for construction of chromosome-specific DNA libraries, including those cloned in bacterial artificial chromosome vectors. Until now, chromosome analysis and sorting using flow cytometry (flow cytogenetics) has found little application in barley (2n = 14, 1C ∼ 5,100 Mbp) because of the impossibility of discriminating and sorting individual chromosomes, except for the smallest chromosome 1H and some translocation chromosomes with DNA content significantly different from the remaining chromosomes. In this work, we demonstrate that wheat–barley ditelosomic addition lines can be used to sort any arm of barley chromosomes 2H–7H. Thus, the barley genome can be dissected into fractions representing only about 6–12% of the total genome. This advance makes the flow cytogenetics an attractive tool, which may greatly facilitate genome analysis and gene cloning in barley.     

Isolation and characterization of microsatellite markers for Cycas hainanensis C. J. Chen (Cycadaceae)

Cycas hainanensis is an endangered cycad species endemic to Hainan Island, China. To enrich our scientific conservation for this species, we developed eight microsatellite markers using repetitive DNA enriched libraries. The number of alleles per microsatellite locus varied from 8 to 17. The expected (H _E ) and observed (H _O ) heterozygosities varied from 0.4754 to 0.8846 and from 0.3636 to 0.9600, respectively. These markers will be employed to determine whether the ex situ C. hainanensis individuals in Sourh China Botanical Garden capture a representative portion of genetic diversity of the wild populations.     

A genetic and physical map of bovine Chromosome 11

A genetic map of bovine Chromosome (Chr) 11 (BTA11, synteny group U16) has been constructed from 330 animals belonging to 21 families, which constitute the international bovine reference panel (IBRP). This map is based on 13 polymorphic microsatellite markers, two of which were chosen in previously published maps. Three markers have been isolated from cosmids. Two of the three cosmids have been physically localized by fluorescence in situ hybridization (FISH), to anchor the genetic map on the chromosome. In addition, a biallelic polymorphism in the -lactoglobulin gene (LGB) has been genetically positioned relative to the microsatellite markers. The most probable order of the markers is: cen-INRA044-BM716-INRA177-(TGLA 327, INRA198, INRA131)-INRA111-INRABERN169-(INRA115, INRA032)-INRA108-INRABERN162-INRA195-LGB. T The total linkage group spans 126 cM, which probably corresponds to most of the chromosome length. The average intermarker distance is about 10.5 cM, allowing the potential detection of a genetic linkage with any Economic Trait Loci (ETL) of this chromosome.     

Isolation and characterization of EST‐derived microsatellite loci from the fungal wheat pathogen Phaeosphaeria nodorum

Eleven polymorphic microsatellite loci and one minisatellite locus originating from expressed sequence tag (EST) libraries of Phaeosphaeria (syn. Stagonospora) nodorum were isolated and characterized. The satellite markers were used to genotype isolates from field populations collected in China, North America and South Africa. The number of alleles per locus ranged from two to 15. Genotype diversity ranged from 87.5 to 95.3 and gene diversity from 0.1 to 0.8. The variable levels of polymorphism within and among populations of P. nodorum renders these 12 satellite loci ideal markers for population genetic analysis of P. nodorum.     

Isolation and characterization of microsatellite markers for Primulina tabacum, a critically endangered perennial herb

Primulina tabacum is a rare and endangered perennial herb with highly restricted limestone distribution in southern China. To enrich our scientific conservation for this species, we developed ten microsatellite markers using repetitive DNA enriched libraries. The number of alleles per microsatellite locus varied from two to six. The expected (H _E) and observed (H _O) heterozygosities varied from 0.4059 to 0.7294 and from 0.1364 to 0.5217, respectively. These markers will be employed in future studies of genetic structure in P. tabacum.