RESUMEN

The difficulty in differentiating the sex of monomorphic bird species has made molecular sexing an important tool in addressing this problem. This method uses noninvasively collected materials such as feathers and may be advantageous for sexing endangered as well as commercialized bird species. In this study, seven primer sets for sexing birds were screened in Aerodramus fuciphagus using a total of 13 feather samples that were randomly selected from the state of Perak, Malaysia. From the screening analysis, only one primer set (P8/WZ/W) successfully differentiated the sex of A. fuciphagus. PCR amplification produced a single 255-bp DNA fragment for males which was derived from CHD-Z (CHD gene region in the sex chromosome Z), while for the females it produced two fragments (144 and 255 bp). The 144-bp fragment was from CHD-W (CHD gene region in the sex chromosome W). Results from sequencing showed no variations in the base sequences of the CHD-W and CHD-Z amplified fragments within the same sexes, except for one male sample (A23) where at position 166, a base substitution occurred (G â†’ A). Phylogenetic analysis of CHD-W showed that four (Apodiformes; Gruiformes; Passeriformes; and Pelecaniformes) out of the five orders investigated had formed four clear clusters within their orders, including the studied order: Apodiformes. Whereas in CHD-Z, four (Accipitriformes; Columbiformes; Galliformes; and Passeriformes) out of five orders investigated formed four clear clusters within their orders, excluding the studied order. In addition, A. fuciphagus and Apus apus (both Apodiformes) showed less divergence in CHD-W than CHD-Z (0% c.f. 9%). The result suggests that in A. fuciphagus, CHD gene evolution occurred at a higher rate in males (CHD-Z) compared to females (CHD-W). This finding may be useful for further studies on sex ratio and breeding management of A. fuciphagus.

RESUMEN

Oil palm breeding has been progressing very well in Southeast Asia, especially in Malaysia and Indonesia. Despite this progress, there are still problems due to the difficulty of controlled crossing in oil palm. Contaminated/illegitimate progeny has appeared in some breeding programs; late and failure of detection by the traditional method causes a waste of time and labor. The use of molecular markers improves the integrity of breeding programs in perennial crops such as oil palm. Four half-sib families with a total of 200 progeny were used in this study. Thirty polymorphic single locus DNA microsatellites markers were typed to identify the illegitimate individuals and to obtain the correct parental and progeny assignments by using the CERVUS and COLONY programs. Three illegitimate palms (1.5%) were found, and 16 loci proved to be sufficient for sibship assignments without parental genotypes by using the COLONY program. The pairwise-likelihood score (PLS) method was better for half-sib family assignments than the full likelihood (FL) method.

Asunto(s)

Arecaceae/genética , Repeticiones de Microsatélite , Fitomejoramiento/métodos , Genotipo

RESUMEN

A preliminary linkage map was constructed by applying backcross and testcross strategy using microsatellite (SSR) markers developed for Xiphophorus and Poecilia reticulata in ornamental fish, molly Poecilia sp. The linkage map having 18 SSR loci consisted of four linkage groups that spanned a map size of 516.1cM. Association between genotypes and phenotypes was tested in a random fashion and QTL for dorsal fin length was found to be linked to locus Msb069 on linkage group 2. Coincidentally, locus Msb069 was also reported as putative homologue primer pairs containing SSRs repeat motif which encoded hSMP-1, a sex determining locus. Dorsal fin length particularly in males of Poecilia latipinna is an important feature during courtship display. Therefore, we speculate that both dorsal fin length and putative hSMP-1 gene formed a close proximity to male sexual characteristics.

Asunto(s)

Aletas de Animales/anatomía & histología , Ligamiento Genético , Poecilia/anatomía & histología , Poecilia/genética , Sitios de Carácter Cuantitativo , Animales , Mapeo Cromosómico/métodos , Mapeo Cromosómico/veterinaria , Femenino , Masculino , Tamaño de los Órganos/genética , Polimorfismo Genético

RESUMEN

Salmonella Enteritidis is a major cause of food poisoning worldwide, and poultry products are the main source of S. Enteritidis contamination for humans. Among the numerous strategies for disease control, improving genetic resistance to S. Enteritidis has been the most effective approach. We investigated the association between S. Enteritidis burden in the caecum, spleen, and liver of young indigenous chickens and seven candidate genes, selected on the basis of their critical roles in immunological functions. The genes included those encoding interleukin 2 (IL-2), interferon-γ (IFN-γ), transforming growth factor ß2 (TGF-ß2), immunoglobulin light chain (IgL), toll-like receptor 4 (TLR-4), myeloid differentiation protein 2 (MD-2), and inducible nitric oxide synthase (iNOS). Two Malaysian indigenous chicken breeds were used as sustainable genetic sources of alleles that are resistant to salmonellosis. The polymerase chain reaction restriction fragment-length polymorphism technique was used to genotype the candidate genes. Three different genotypes were observed in all of the candidate genes, except for MD-2. All of the candidate genes showed the Hardy-Weinberg equilibrium for the two populations. The IL-2-MnlI polymorphism was associated with S. Enteritidis burden in the caecum and spleen. The TGF-ß2-RsaI, TLR-4-Sau 96I, and iNOS-AluI polymorphisms were associated with the caecum S. Enteritidis load. The other candidate genes were not associated with S. Enteritidis load in any organ. The results indicate that the IL-2, TGF-ß2, TLR-4, and iNOS genes are potential candidates for use in selection programmes for increasing genetic resistance against S. Enteritidis in Malaysian indigenous chickens.

Asunto(s)

Pollos/genética , Polimorfismo de Longitud del Fragmento de Restricción/genética , Enfermedades de las Aves de Corral/inmunología , Salmonelosis Animal/inmunología , Salmonella enteritidis/patogenicidad , Animales , Pollos/inmunología , Pollos/microbiología , Cartilla de ADN/genética , Frecuencia de los Genes , Genotipo , Cadenas Ligeras de Inmunoglobulina/genética , Interferón gamma/genética , Interleucina-2/genética , Intestino Grueso/microbiología , Modelos Lineales , Hígado/microbiología , Antígeno 96 de los Linfocitos/genética , Malasia , Óxido Nítrico Sintasa de Tipo II/genética , Enfermedades de las Aves de Corral/genética , Enfermedades de las Aves de Corral/microbiología , Salmonelosis Animal/genética , Salmonelosis Animal/microbiología , Salmonella enteritidis/inmunología , Bazo/microbiología , Receptor Toll-Like 4/genética , Factor de Crecimiento Transformador beta2/genética

RESUMEN

A study of genetic variation among 10 pairs of chromosomes extracted from 13 tropical sweet corn inbred lines, using 99 microsatellite markers, revealed a wide range of genetic diversity. Allelic richness and the number of effective alleles per chromosome ranged from 2.78 to 4.33 and 1.96 to 3.47, respectively, with respective mean values of 3.62 and 2.73. According to the Shannon's information index (I) and Nei's gene diversity coefficient (Nei), Chromosome 10 was the most informative chromosome (I = 1.311 and Nei = 0.703), while Chromosome 2 possessed the least (I = 0.762 and Nei = 0.456). Based on linkage disequilibrium (LD) measurements for loci less than 50 cM apart on the same chromosome, all loci on Chromosomes 1, 6 and 7 were in equilibrium. Even so, there was a high proportion of genetic variation in Chromosomes 4, 5, 8, 9 and 10, thereby revealing their appropriateness for use in the genetic diversity investigations among tropical sweet corn lines. Chromosome 4, with the highest number of loci in linkage disequilibrium, was considered the best for marker-phenotype association and QTL mapping, followed by Chromosomes 5, 8, 9 and 10.