Biomedical subjects

Mauricio Ulloa

Publications and source records attributed to Mauricio Ulloa.

4 recordsLinked to original sources

PubMed2006

CMD: a Cotton Microsatellite Database resource for Gossypium genomics.

BACKGROUND: The Cotton Microsatellite Database (CMD) http://www.cottonssr.org is a curated and integrated web-based relational database providing centralized access to publicly available cotton microsatellites, an invaluable resource for basic and applied research in cotton breeding. DESCRIPTION: At present CMD contains publication, sequence, primer, mapping and homology data for nine major cotton microsatellite projects, collectively representing 5,484 microsatellites. In addition, CMD displays data for three of the microsatellite projects that have been screened against a panel of core germplasm. The standardized panel consists of 12 diverse genotypes including genetic standards, mapping parents, BAC donors, subgenome representatives, unique breeding lines, exotic introgression sources, and contemporary Upland cottons with significant acreage. A suite of online microsatellite data mining tools are accessible at CMD. These include an SSR server which identifies microsatellites, primers, open reading frames, and GC-content of uploaded sequences; BLAST and FASTA servers providing sequence similarity searches against the existing cotton SSR sequences and primers, a CAP3 server to assemble EST sequences into longer transcripts prior to mining for SSRs, and CMap, a viewer for comparing cotton SSR maps. CONCLUSION: The collection of publicly available cotton SSR markers in a centralized, readily accessible and curated web-enabled database provides a more efficient utilization of microsatellite resources and will help accelerate basic and applied research in molecular breeding and genetic mapping in Gossypium spp.

Chromosome Mapping↗

PubMed2006

Cotton genome mapping with new microsatellites from Acala 'Maxxa' BAC-ends.

Fine mapping and positional cloning will eventually improve with the anchoring of additional markers derived from genomic clones such as BACs. From 2,603 new BAC-end genomic sequences from Gossypium hirsutum Acala 'Maxxa', 1,316 PCR primer pairs (designated as MUSB) were designed to flank microsatellite or simple sequence repeat motif sequences. Most (1164 or 88%) MUSB primer pairs successfully amplified DNA from three species of cotton with an average of three amplicons per marker and 365 markers (21%) were polymorphic between G. hirsutum and G. barbadense. An interspecific RIL population developed from the above two entries was used to map 433 marker loci and 46 linkage groups with a genetic distance of 2,126.3 cM covering approximately 45% of the cotton genome and an average distance between two loci of 4.9 cM. Based on genome-specific chromosomes identified in G. hirsutum tetraploid (A and D), 56.9% of the coverage was located on the A subgenome while 39.7% was assigned to the D subgenome in the genetic map, suggesting that the A subgenome may be more polymorphic and recombinationally active than originally thought. The linkage groups were assigned to 23 of the 26 chromosomes. This is the first genetic map in which the linkage groups A01 and A02/D03 have been assigned to specific chromosomes. In addition the MUSB-derived markers from BAC-end sequences markers allows fine genetic and QTL mapping of important traits and for the first time provides reconciliation of the genetic and physical maps. Limited QTL analyses suggested that loci on chromosomes 2, 3, 12, 15 and 18 may affect variation in fiber quality traits. The original BAC clones containing the newly mapped MUSB that tag the QTLs provide critical DNA regions for the discovery of gene sequences involved in biological processes such as fiber development and pest resistance in cotton.

Chromosomes, Artificial, Bacterial↗

PubMed2005

Genetic mapping of new cotton fiber loci using EST-derived microsatellites in an interspecific recombinant inbred line cotton population.

There is an immediate need for a high-density genetic map of cotton anchored with fiber genes to facilitate marker-assisted selection (MAS) for improved fiber traits. With this goal in mind, genetic mapping with a new set of microsatellite markers [comprising both simple (SSR) and complex (CSR) sequence repeat markers] was performed on 183 recombinant inbred lines (RILs) developed from the progeny of the interspecific cross Gossypium hirsutum L. cv. TM1 x Gossypium barbadense L. Pima 3-79. Microsatellite markers were developed using 1557 ESTs-containing SSRs (> or = 10 bp) and 5794 EST-containing CSRs (> or = 12 bp) obtained from approximately 14,000 consensus sequences derived from fiber ESTs generated from the cultivated diploid species Gossypium arboreum L. cv AKA8401. From a total of 1232 EST-derived SSR (MUSS) and CSR (MUCS) primer-pairs, 1019 (83%) successfully amplified PCR products from a survey panel of six Gossypium species; 202 (19.8%) were polymorphic between the G. hirsutum L. and G. barbadense L. parents of the interspecific mapping population. Among these polymorphic markers, only 86 (42.6%) showed significant sequence homology to annotated genes with known function. The chromosomal locations of 36 microsatellites were associated with 14 chromosomes and/or 13 chromosome arms of the cotton genome by hypoaneuploid deficiency analysis, enabling us to assign genetic linkage groups (LG) to specific chromosomes. The resulting genetic map consists of 193 loci, including 121 new fiber loci not previously mapped. These fiber loci were mapped to 19 chromosomes and 11 LG spanning 1277 cM, providing approximately 27% genome coverage. Preliminary quantitative trait loci analysis suggested that chromosomes 2, 3, 15, and 18 may harbor genes for traits related to fiber quality. These new PCR-based microsatellite markers derived from cotton fiber ESTs will facilitate the development of a high-resolution integrated genetic map of cotton for structural and functional study of fiber genes and MAS of genes that enhance fiber quality.

Aneuploidy↗

PubMed2003

The DNA sequence of a gypsy element from Gossypium hirsutum L. and characterization of gypsy elements in three Gossypium species.

A strategy was developed to isolate a complete gypsy-element from Gossypium hirsutum L. based on the sequence of a RAPD that was polymorphic in near isoganic lines of cotton that varied in leaf shape. A 5998 nt clone was isolated and its gene order and sequence confirmed it was a gypsy-type retroelement. Sequences homologous to the gag portion of this clone were also found in Gossypium herbaceum L. and Gossypium raimondii L. A portion of the open reading frame of the integrase gene was amplified from three Gossypium species under investigation. PCR products of the expected size were amplified from all three Gossypium species. G. raimondii sequences were statistically more degenerate than sequences from either G. hirsutum or G. herbaceum. Finally, analysis of the open reading frames of selected integrase clones from the three Gossypium species revealed a second gypsy element based on similarity of the deduced amino acid sequence.

Base Sequence↗