Molecular genetic diversity and differentiation of Nile tilapia (Oreochromis niloticus, L. 1758) in East African natural and stocked populations
Background The need for enhancing the productivity of fisheries in Africa triggered the introduction of non-native fish, causing dramatic changes to local species. In East Africa, the extensive translocation of Nile tilapia (Oreochromis niloticus) is one of the major factors in this respect. Using 40 microsatellite loci with SSR-GBS techniques, we amplified a total of 664 individuals to investigate the genetic structure of O. niloticus from East Africa in comparison to Ethiopian and Burkina Faso populations. Results All three African regions were characterized by independent gene-pools, however, the Ethiopian population from lake Tana showed to be more divergent than expected suggesting that it might be a different species. In East Africa, the genetic structure was congruent with both geographical location and anthropogenic activities. O. niloticus from Lake Turkana (Kenya) was isolated, while in Uganda, despite populations being rather similar to each other, two main natural catchments were able to be defined. We show that these two groups contributed to the gene-pool of different non-native populations. Moreover, admixture and possible hybridization with other tilapiine species may have contributed to the genetic divergence found in some populations such as Lake Victoria. We detected other factors that might be affecting Nile tilapia genetic variation. For example, most of the populations have gone through a reduction of genetic diversity, which can be a consequence of bottleneck caused by overfishing, genetic erosion due to fragmentation or founder effect resulting from stoking activities. Conclusions The anthropogenic activities particularly in the East African O. niloticus translocations, promoted admixture and contact with the native congenerics which may contribute to outbreeding depression and hence compromising the sustainability of the species in the region.
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Great work. Please I also want to do similar work on macrobrachium vollenhovenii along osun River and Lagos lagoon in Nigeria, can you assist in training on the methodology. Thank you.
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Molecular genetic diversity and differentiation of Nile tilapia (Oreochromis niloticus, L. 1758) in East African natural and stocked populations
Posted 03 Jan, 2020
On 30 Jan, 2020
On 16 Jan, 2020
On 18 Dec, 2019
On 17 Dec, 2019
On 17 Dec, 2019
On 17 Dec, 2019
On 28 Nov, 2019
On 27 Nov, 2019
On 27 Nov, 2019
On 08 Nov, 2019
Received 26 Oct, 2019
On 21 Oct, 2019
Received 21 Oct, 2019
On 08 Oct, 2019
Invitations sent on 07 Oct, 2019
On 03 Oct, 2019
On 02 Oct, 2019
On 02 Oct, 2019
On 01 Sep, 2019
Received 29 Aug, 2019
Received 19 Aug, 2019
Received 19 Aug, 2019
On 02 Aug, 2019
On 02 Aug, 2019
Invitations sent on 28 Jul, 2019
On 28 Jul, 2019
On 19 Jul, 2019
On 05 Jul, 2019
On 04 Jul, 2019
On 03 Jul, 2019
Background The need for enhancing the productivity of fisheries in Africa triggered the introduction of non-native fish, causing dramatic changes to local species. In East Africa, the extensive translocation of Nile tilapia (Oreochromis niloticus) is one of the major factors in this respect. Using 40 microsatellite loci with SSR-GBS techniques, we amplified a total of 664 individuals to investigate the genetic structure of O. niloticus from East Africa in comparison to Ethiopian and Burkina Faso populations. Results All three African regions were characterized by independent gene-pools, however, the Ethiopian population from lake Tana showed to be more divergent than expected suggesting that it might be a different species. In East Africa, the genetic structure was congruent with both geographical location and anthropogenic activities. O. niloticus from Lake Turkana (Kenya) was isolated, while in Uganda, despite populations being rather similar to each other, two main natural catchments were able to be defined. We show that these two groups contributed to the gene-pool of different non-native populations. Moreover, admixture and possible hybridization with other tilapiine species may have contributed to the genetic divergence found in some populations such as Lake Victoria. We detected other factors that might be affecting Nile tilapia genetic variation. For example, most of the populations have gone through a reduction of genetic diversity, which can be a consequence of bottleneck caused by overfishing, genetic erosion due to fragmentation or founder effect resulting from stoking activities. Conclusions The anthropogenic activities particularly in the East African O. niloticus translocations, promoted admixture and contact with the native congenerics which may contribute to outbreeding depression and hence compromising the sustainability of the species in the region.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Great work. Please I also want to do similar work on macrobrachium vollenhovenii along osun River and Lagos lagoon in Nigeria, can you assist in training on the methodology. Thank you.