The relationship between domestication and genetic diversity of Oreochromis species in Malawi: Oreochromis shiranus shiranus (Boulener) and Oreochromis shiranus chilwae (Trewavas).
| dc.contributor.author | Ambali, Aggrey John Douglas. | en_US |
| dc.contributor.degree | Ph.D. | en_US |
| dc.date.accessioned | 2014-10-21T12:37:15Z | |
| dc.date.available | 1996 | |
| dc.date.issued | 1996 | en_US |
| dc.description | The fish species domesticated in most African aquaculture activities have not been genetically identified and characterized; and the distribution of their genetic diversity is not known. As a result there is continuous mixing of otherwise genetically differentiated strains leading to loss of between-population genetic variation. In this study, microsatellite DNA markers for tilapia were developed to analyze genetic diversity of wild and domesticated populations of O. shiranus species in Malawi. | en_US |
| dc.description | The primers developed with O. shiranus DNA amplified microsatellites in other species of the tilapiine fishes. Genetic relationships among populations of O. shiranus in Malawi were determined and it was observed that the populations in Lakes Chilwa and Chiuta belonged to O. shiranus chilwae while the population in Lake Malombe belonged to O. shiranus shiranus. | en_US |
| dc.description | Measures of genetic diversity declined in the domesticated populations compared to wild populations. The loss of diversity was correlated with the time elapsed since the founding of farm stock and population genetic differentiation was also strongly influenced by the pattern of known exchange of germplasm among farms. Social factors, as measured by transfer proximity, are the key determinants of genetic distance, not geographic distance. Genetic diversity in the reservoir populations declined with increase in predator populations which were stocked either artificially to control tilapia populations, or naturally through streams. Uncontrolled transfer of germplasm between reservoirs resulted in genetic contamination of the populations. | en_US |
| dc.description | Socio-economic analysis of small scale farms in Malawi showed that growout operations were economically viable primarily because pond inputs comprised recycled on-farm and household waste. The predominance of integrated crop/livestock/fish farming system was a favorable indicator of the possibility of involving farmers in community-based aquaculture biodiversity conservation programs at farm level. The programs would benefit from the knowledge and experience farmers had already acquired in conserving indigenous breeds of livestock and crops. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1996. | en_US |
| dc.identifier.other | AAINN15812 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55104 | |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | en_US | |
| dc.subject | Biology, Genetics. | en_US |
| dc.subject | Biology, Zoology. | en_US |
| dc.subject | Agriculture, Fisheries and Aquaculture. | en_US |
| dc.title | The relationship between domestication and genetic diversity of Oreochromis species in Malawi: Oreochromis shiranus shiranus (Boulener) and Oreochromis shiranus chilwae (Trewavas). | en_US |
| dc.type | text | en_US |
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