Genetic diversity and population structure in multiple Chinese goat populations using a SNP panel

Information about genetic diversity and population structure among goat breeds is essential for genetic improvement, understanding of environmental adaptation as well as utilization and conservation of goat breeds. Here, we measured genetic diversity and population structure in multiple Chinese goat populations, namely, Nanjiang, Qinggeda, Arbas Cashmere, Jining Grey, Luoping Yellow and Guangfeng goats. A total of 193 individuals were genotyped for about 47 401 autosomal single nucleotide polymorphisms (SNPs). We found a high proportion of informative SNPs, ranging from 69.5% in the Luoping Yellow to 93.9% in the Jining Grey goat breeds with an average mean of 84.7%. Diversity, as measured by expected heterozygosity, ranged from 0.371 in Luoping Yellow to 0.405 in Jining Grey goat populations. The average estimated pair-wise genetic differentiation (F_ST ) among the populations was 8.6%, ranging from 0.2% to 16% and indicating low to moderate genetic differentiation. Principal component analysis, genetic structure and phylogenetic tree analysis revealed a clustering of six Chinese goat populations according to geographic distribution. The results from this study can contribute valuable genetic information and can properly assist with within-breed diversity, which provides a good opportunity for sustainable utilization of and maintenance of genetic resource improvements in the Chinese goat populations.

Detection of trypanosome DNA in serologically positive but aparasitaemic horses suspected of dourine in Ethiopia

A field study of horses was conducted in the province of Bale, Ethiopian highlands. A rapid questionnaire analysis indicated that dourine, known as "Dirressa", is a major health problem of equines in this area. A total of 121 horses suspected of dourine were examined by use of clinical, parasitological, serological and DNA based techniques. Incoordination of hindlegs (76%), swelling of external genitalia (48.8%) and emaciation (39.7%) were the most common clinical signs observed. Using the haematocrit centrifugation technique (HCT), no trypanosomes were detected in blood, genital washes or tissue fluids. By contrast, trypanosome specific DNA products were amplified by PCR and subsequently detected by DNA probe hybridization in blood samples of 29 horses (29/104), all serologically positive by CFT and/or ELISA. Positive PCR results were significantly associated with swelling of external genitalia (P< 0.05). There is strong evidence, although there was no direct detection of T. equiperdum, that dourine is highly prevalent in the area, a finding which is in accordance with earlier reports. It is concluded, that this PCR assay provides a very sensitive tool in the diagnosis of active infections of dourine in endemic areas where trypanocidal drug use is common.