Genetic identification of strains and genotypes of buffaloes and goats in south east Asia

• University of Malaya, Malaysia
• Universiti Pertanian Malaysia, Malaysia

Currently, countries in Southeast Asia have considerable interest in improving the productivity of buffaloes - for draught power, meat and milk - and of goats. To achieve improvement by genetic means initially requires evaluation of the productivity of the various breeds and strains and of the potential value of cross-breeding.
Productivity evaluations in progress in Southeast Asia cannot be validly compared, as we have no knowledge of the genetic similarity of animals from the different countries. The wealth of strains there and their geographic isolation, together with the limited technical and financial resources in the region, make it impossible to evaluate all of them. Accordingly, this project will determine the genetic interrelations among the breeds, strains and populations of swamp buffalo and goats, in order to group these into sets that are genetically similar and then to compare representatives from each set.
The river buffalo has a diploid chromosome number of 50, while almost all the swamp buffalo thus far have a diploid number of 48. Experience with other domestic animals suggests that cross-breeding the two could lead to a decrease in reproductive efficiency, a reduction in genetic recombination, or abnormal segregation of the genetic material during gamete formation. Such problems can result from non-homologous chromosome pairing or multivalent formation during meiosis, and their magnitude could affect the success of a proposed cross-breeding program. This project will therefore analyse the patterns of inheritance of biochemical markers and chromosomal segregation in F1, F2 and back-cross river X swamp buffaloes.
A third component of the project - correlating the presence of biochemical alleles and chromosome composition with performance in terms of economic traits such as draught power, reproduction, milk production or feed utilisation - will use all animals in project 8515 for both biochemical and chromosomal analysis.
The scientists will estimate gene frequencies at biochemical loci in populations of swamp buffalo and goats, sampling 50 individuals from each population at a number of sites in Indonesia, Malaysia, the Philippines, Thailand and Sri Lanka and from Australian swamp buffalo. They will use cellulose acetate electrophoresis and karyotyping - mainly at Kuala Lumpur and Armidale - to investigate genetic variation for at least 30 loci in each population. The resulting estimates of genetic distances could also prove useful in predicting the expected heterosis in crosses between populations.
Detailed cytogenetic studies - blood chromosome analyses, meiotic chromosome and synaptonemal complex analysis - on F1, F2 and back-cross buffaloes with 48, 49 and 50 chromosome constitutions - should identify exact segration patterns and determine whether different karyotypes exist. Correlation of these karyotypic data with the electrophoretic data collected from the same animals should reveal the pattern of inheritance in the various chromosomal types.
The team will also study semen characterisitics of cross-bred bulls to check for reduced sperm counts related to unbalanced gamete formation, and undertake a survey of the chromosome status of the Sri Lankan buffalo populations sampled to expand the current data on diploid number.
Using standard methods, scientists at the Universiti Pertanian Malaysia will collect chromosome preparations for karyotyping, G-band analysis and light microscope analysis of male meiosis. Others, at CSIRO, have established protocols for high-resolution R-banding of somatic chromosome preparations for short-term cattle blood leucocyte cultures and the application of electron microscopy for analysing male and female meiosis. These two groups have collaborated in preliminary work to adapt the methods for analysing meiosis with the electron microscope for use with buffalo samples.
The information collected during this study will benefit all groups working on improvement or evaluation of buffaloes and goats within Southeast Asia.