George Wanjala

Mr. George Wanjala

orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
17 November 2022 in Saudi Journal of Biological Sciences
Verified
Journal Article
Open access
GWGeorge Wanjala
George Wanjala
PAPutri Kusuma Astuti
Putri Kusuma Astuti
ZBZoltán Bagi
Zoltán Bagi
NKNelly Kichamu
Nelly Kichamu
SSStrausz Strausz
Strausz Strausz
SKSzilvia Kusza
Szilvia Kusza
Climate change has a significant effect on the productivity of livestock including milk, meat, and reproduction. This could be attributed to the internal diversion of energy resources towards adaptive mechanisms. Among the climate change variables, thermal stress seems to be the major limiting factor in animal agriculture. A better understanding of the effects of climate change-influenced ecological factors on the genetic diversity of livestock species is warranted. Sheep is an ideal livestock species to be used in investigating environmental adaptation due to its wide range of agroecological habitats, genetic and phenotypic variability. There is a heavy reliance on sheep genetic diversity for future animal protein security, but the implications of climate change on their genetic diversity receive less attention.

5 June 2024 in Biology
Verified
Journal Article
Open access
PDF file
NKNELLY KICHAMU
NELLY KICHAMU
PAPutri Kusuma Astuti
Putri Kusuma Astuti
GWGeorge Wanjala
George Wanjala
SSStrausz Strausz
Strausz Strausz
ZBZoltán Bagi
Zoltán Bagi
SKSzilvia Kusza
Szilvia Kusza
Indigenous goats are important in the livelihoods of rural households in East African countries. This is due to their ability to produce and reproduce in different environments and climatic conditions. Even though these indigenous goats are important, there is little available information on the genetic characterization of these breeds in Africa and at the international level. This paper reviews the status of indigenous goats, highlighting their production systems, phenotypic and genetic characteristics, and genetic diversity, and proposes potential ways for sustainable improvement and conservation in East African countries. Most households use traditional production systems with various uncharacterized goat breeds and ecotypes, which are hence named after the tribe or locality in which they are found. Most of these goats are classified as small East African breeds, with significant variability in morphological features. Some of the challenges to goat production in this region are indiscriminate crossbreeding, lack of pedigree records, parasites and disease incidences, low-quality pastures, and low levels of management. There is a need for a collaborative approach amongst the actors in goat breeding value chains as well as integrating modern genomic tools into breeding programs to enhance selection. This will ensure the resilience and sustainability of these unique indigenous goat populations in East Africa

10 August 2021 in Biology
Verified
Journal Article
Open access
PDF file
GWGeorge Wanjala
George Wanjala
ZBZoltán Bagi
Zoltán Bagi
SKSzilvia Kusza
Szilvia Kusza
To improve sheep breeding and conservation of genetic resources, the mitochondrial DNA control region (mtDNA CR) of 399 sequences of African indigenous sheep breeds from previously published research articles were meta-analyzed to elucidate their phylogenetic relationship, diversity, and demographic history. A total of 272 haplotypes were found, of which 207 were unique and a high level of mtDNA CR variability was observed. Generally, the number of polymorphic sites, nucleotide and haplotype diversity were high (284, 0.254 ± 0.012 and 0.993 ± 0.002, respectively). The median-joining (MJ) network of haplotypes produced three major haplogroups (A, B and C), with haplogroup B being dominant. A mixture of populations suggests a common matrilineal origin and lack of and/or a weak phylogeographic structure. Mismatch analysis showed recent expansion of North African breeds, whereas East African and continental populations exhibited selection pressures for adaptation. A slight historical genetic difference was also observed between the fat tail and thin tail sheep breeds. However, further investigations are required using more samples and long sequence segments to achieve deeper levels of conclusions on the African sheep phylogenetic relationship. The present meta-analysis results contribute to the general understanding of African native sheep populations for improved management of sheep genetic resources.

28 February 2023 in Biology
Verified
Journal Article
Open access
PDF file
GWGeorge Wanjala
George Wanjala
PAPutri Kusuma Astuti
Putri Kusuma Astuti
ZBZoltán Bagi
Zoltán Bagi
NKNELLY KICHAMU
NELLY KICHAMU
SSStrausz Strausz
Strausz Strausz
SKSzilvia Kusza
Szilvia Kusza
Dorper sheep was developed for meat production in arid and semi-arid regions under extensive production systems in South Africa. Two variants with distinct head and neck colors were bred during their development process. White Dorper have a white coat while Dorper have a black head and neck. Both variants have grown in popularity around the world. Therefore, understanding the genomic architecture between South African Dorpers and Dorper populations adapted to other climatic regions, as well as genomic differences between Dorper and White Dorper variants is vital for their molecular management. Using the ovine 50K SNP chip, this study compared the genetic architecture of Dorper variants between populations from South Africa and Hungary. The Dorper populations in both countries had high genetic diversity levels, although Dorper in Hungary showed high levels of inbreeding. White Dorpers from both countries were genetically closely related, while Dorpers were distantly related according to principal component analysis and neighbor-joining tree. Additionally, whereas all groups displayed unique selection signatures for local adaptation, Dorpers from Hungary had a similar linkage disequilibrium decay. Environmental differences and color may have influenced the genetic differentiation between the Dorpers. For their molecular management and prospective genomic selection, it is crucial to understand the Dorper sheep’s genomic architecture, and the results of this study can be interpreted as a step in this direction.

19 August 2024 in Animals
Verified
Journal Article
Open access
PDF file
LPLenox Pius
Lenox Pius
SHShuntao Huang
Shuntao Huang
GWGeorge Wanjala
George Wanjala
ZBZoltán Bagi
Zoltán Bagi
SKSzilvia Kusza
Szilvia Kusza
Africa is home to a wide diversity of locally adapted pig breeds whose genetic architecture offers important insights into livestock adaptation to climate change. However, the majority of these inherent traits have not been fully highlighted. This review presents an overview of the current state of African pig genetic resources, providing highlights on their population and production statistics, production system, population diversity indices, and genomic evidence underlying their evolutionary potential. The study results reveal an incomplete characterization of local pig genotypes across the continent. The characterized population, however, demonstrates moderate to high levels of genetic diversity, enough to support breeding and conservation programs. Owing to low genetic differentiation and limited evidence of distinct population structures, it appears that most local pig populations are strains within larger breeds. Genomic evidence has shown a higher number of selection signatures associated with various economically important traits, thus making them potential candidates for climate change adaptation. The reportedly early evidence of hybridization with wild suid groups further suggests untapped insights into disease resistance and resilience traits that need to be illuminated using higher-density markers. Nevertheless, gene introgression from commercial breeds is prevalent across Africa; thus, efforts to realize and utilize these traits must increase before they are permanently depleted.

15 January 2023 in Animals
Verified
Journal Article
Open access
PDF file
GWGeorge Wanjala
George Wanjala
NKNELLY KICHAMU
NELLY KICHAMU
LCLudovic Toma Cziszter
Ludovic Toma Cziszter
PAPutri Kusuma Astuti
Putri Kusuma Astuti
SKSzilvia Kusza
Szilvia Kusza
This comparative study aimed to evaluate genetic and environmental factors’ effects on the growth traits of lambs in Dorper and Red Maasai (RedM) sheep breeds. The data analyzed contained the following measurements: birth weight (Bwt), weaning weight (Wwt), yearling weight (Ywt), birth type (single or twins), and details on each lamb’s dam (dam ID and age) and sire. Except for the RedM, whose birth weight decreased with time, both breeds generally showed an increase in other growth weights across the study period, with yearly variations affecting both breeds. Additionally, analysis by a linear mixed model with restricted maximum likelihood (REML) showed that only breed as a factor significantly (p < 0.05) influenced birth weight; breed, sex, and birth type all significantly (p < 0.05) influenced weaning weight, whereas season, sex, and dam age significantly (p < 0.05) influenced yearling weight. The RedM breed outperformed the Dorper breed in post-weaning growth rate, demonstrating early resilience and adaptation to local environmental factors independent of maternal influence. Breed and non-genetic factors play a vital role in the growth of lambs, and the results of this study offer an opportunity for improved farm management under an extensive production system and selection for the conservation of the indigenous Red Maasai breed.