Samer Alasaad

Dr. Samer Alasaad


Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

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

Representative Publications

View All Publications
27 October 2017 in Evolutionary Applications
Verified
Journal Article
Open access
PDF file
CGChristine Grossen
Christine Grossen
IBIris Biebach
Iris Biebach
SASamer Alasaad
Samer Alasaad
LKLukas F. Keller
Lukas F. Keller
DCDaniel Croll
Daniel Croll
Restoration of lost species ranges to their native distribution is key for the survival of endangered species. However, reintroductions often fail and long‐term genetic consequences are poorly understood. Alpine ibex (Capra ibex) are wild goats that recovered from <100 individuals to ~50,000 within a century by population reintroductions. We analyzed the population genomic consequences of the Alpine ibex reintroduction strategy. We genotyped 101,822 genomewide single nucleotide polymorphism loci in 173 Alpine ibex, the closely related Iberian ibex (Capra pyrenaica) and domestic goat (Capra hircus). The source population of all Alpine ibex maintained genetic diversity comparable to Iberian ibex, which experienced less severe bottlenecks. All reintroduced Alpine ibex populations had individually and combined lower levels of genetic diversity than the source population. The reintroduction strategy consisted of primary reintroductions from captive breeding and secondary reintroductions from established populations. This stepwise reintroduction strategy left a strong genomic footprint of population differentiation, which increased with subsequent rounds of reintroductions. Furthermore, analyses of genomewide runs of homozygosity showed recent inbreeding primarily in individuals of reintroduced populations. We showed that despite the rapid census recovery, Alpine ibex carry a persistent genomic signature of their reintroduction history. We discuss how genomic monitoring can serve as an early indicator of inbreeding.

10 March 2014 in PLOS ONE
Verified
Journal Article
Open access
PDF file
MMMatthew Mutinda
Matthew Mutinda
GCGeoffrey Chenge
Geoffrey Chenge
FGFrancis Gakuya
Francis Gakuya
MOMoses Otiende
Moses Otiende
POPatrick Omondi
Patrick Omondi
SASamer Alasaad
Samer Alasaad
Human-elephant conflict (HEC) is a recurring problem that appears wherever the range of elephants and humans overlap. Different methods including the use of electric fences are used worldwide to mitigate this conflict. Nonetheless, elephants learn quickly that their tusks do not conduct electricity and use them to break down fences (fence-breakers). In Lewa Wildlife Conservancy, Kenya, destructive elephants (Loxodonta africana) were monitored between 2010 and 2013. The fence-breaking rate reached four incidents (fence-breaking) per elephant per 100 days. Ten bull males and 57 females were identified as fence-breakers. The bulls were involved in 85.07% and the females in 14.93% of incidents. The Kenya Wildlife Service approved detusking (partial cutting of tusks) in four of the 10 fence-breakers as a way of preventing them from breaking down fences, thereby mitigating HEC in the Conservancy. The result of the detusking was a drastic six-fold reduction in damage to fences (range: 1.67 to 14.5 times less fence-breaking) by the four worst fence-breaker elephants, because with trimmed tusks elephants lack the tools to break down fences. Detusking could not totally eliminate fence destruction because, despite lacking their tools, elephants can still destroy fences using their heads, bodies and trunks, albeit less effectively. On the other hand, apart from inherent aesthetic considerations, the detusking of elephants may have certain negative effects on factors such as elephants' social hierarchies, breeding, mate selection and their access to essential minerals and food. Elephant detusking seems to be effective in drastically reducing fence-breaking incidents, nonetheless its negative effects on behaviour, access to food and its aesthetical consequences still need to be further studied and investigated.

10 June 2011 in Parasites & Vectors
Verified
Journal Article
Open access
PDF file
LALin Ai
Lin Ai
MCMu-Xin Chen
Mu-Xin Chen
SASamer Alasaad
Samer Alasaad
HEHany Elsheikha
Hany Elsheikha
JLJuan Li
Juan Li
JCJia xu chen
Jia xu chen
Liver flukes belonging to the genusFasciolaare among the causes of foodborne diseases of parasitic etiology. These parasites cause significant public health problems and substantial economic losses to the livestock industry. Therefore, it is important to definitively characterize theFasciolaspecies. Current phenotypic techniques fail to reflect the full extent of the diversity ofFasciolaspp. In this respect, the use of molecular techniques to identify and differentiateFasciolaspp. offer considerable advantages. The advent of a variety of molecular genetic techniques also provides a powerful method to elucidate many aspects ofFasciolabiology, epidemiology, and genetics. However, the discriminatory power of these molecular methods varies, as does the speed and ease of performance and cost. There is a need for the development of new methods to identify the mechanisms underpinning the origin and maintenance of genetic variation within and amongFasciolapopulations. The increasing application of the current and new methods will yield a much improved understanding ofFasciolaepidemiology and evolution as well as more effective means of parasite control. Herein, we provide an overview of the molecular techniques that are being used for the genetic characterization, detection and genotyping ofFasciolaspp..

1 July 2013 in Infection, Genetics and Evolution
Verified
Journal Article
Closed access
SASamer Alasaad
Samer Alasaad
LRLuca Rossi
Luca Rossi
Jorg HeukelbachJorg Heukelbach
Jorg Heukelbach
JPJesús M. Pérez
Jesús M. Pérez
Omar HamarshehOmar Hamarsheh
Omar Hamarsheh
XZXing-Quan Zhu
Xing-Quan Zhu

27 April 2014 in BMC Veterinary Research
Verified
Journal Article
Open access
PDF file
CSChang-Chun Shao
Chang-Chun Shao
MXMin-Jun Xu
Min-Jun Xu
SASamer Alasaad
Samer Alasaad
HSHui-Qun Song
Hui-Qun Song
LPLifei Peng
Lifei Peng
XZXing-Quan Zhu
Xing-Quan Zhu
The parasitic nematodes Ascaris lumbricoides and A. suum are of great public health and economic significance, and the two taxa were proposed to represent a single species. miRNAs are known with functions of gene regulations at post-transcriptional level. We herein compared the miRNA profiles of A. lumbricoides and A. suum female adults by Solexa deep sequencing combined with bioinformatics analysis and stem-loop real-time PCR. Using the A. suum genome as the reference genome, we obtained 171 and 494 miRNA candidates from A. lumbricoides and A. suum, respectively. Among which, 74 miRNAs were shared between the two taxa, 97 and 420 miRNAs were A. lumbricoides and A. suum specific. Target and function prediction revealed a significant set of targets which are related to ovarian message protein, vitellogenin and chondroitin proteoglycan of the two nematodes. Enrichment analysis revealed that the percentages of most predicted functions of the miRNA targets were similar, with some taxon specific or taxon enhanced functions, such as different target numbers, specific functions (NADH dehydrogenase and electron carrier functions), etc. This study characterized comparatively the miRNAs of adult A. lumbricoides and A. suum, and the findings provide additional evidence that A. lumbricoides and A. suum represent a single species. Due to the fast evolution nature of miRNAs and the different parasitic living conditions of humans and pigs, the phenomenon above might indicate a fast evolution of miRNAs of Ascaris in humans and pigs.

1 May 2011 in International Journal of Infectious Diseases
Verified
Journal Article
Closed access
SASamer Alasaad
Samer Alasaad
SWShelley Walton
Shelley Walton
LRLuca Rossi
Luca Rossi
SBSet Bornstein
Set Bornstein
MAMarawan Abu-Madi
Marawan Abu-Madi
Jorg HeukelbachJorg Heukelbach
Jorg Heukelbach