Michael Seifu | Addis Ababa University (original) (raw)
Papers by Michael Seifu
Primates, 1993
A 12-year-old female chimpanzee (Pan troglodytes schweinfurthii) of M-Group in the Mahale Mountai... more A 12-year-old female chimpanzee (Pan troglodytes schweinfurthii) of M-Group in the Mahale Mountains National Park, Tanzania was seen to rouse, capture, and eat a squirrel hiding in the narrow hole of a tree. The kill was aided by the use of a sturdy tool modified from a branch of the same tree. This appears to be the first reported case for chimpanzees, or any other nonhuman primate, of tool-use that directly led to the capture of a mammalian prey species. This behavior is discussed in relation to possible factors contributing to the occurrence of tool-use in small mammal predation especially by females to exploit a low competition meat source.
International Journal of Primatology, 1996
Swallowing whole leaves by chimpanzees and other African apes has been hypothesized to have an an... more Swallowing whole leaves by chimpanzees and other African apes has been hypothesized to have an antiparasitic or medicinal function, but detailed studies demonstrating this were lacking. We correlate for the first time quantifiable measures of the health of chimpanzees with observations of leaf-swallowing in Mahale Mountains National Park, Tanzania. We obtained a total of 27 cases involving the use ofAspilia mossambicensis (63%),Lippia plicata (7%),Hibiscus sp. (15%),Trema orientalis (4%), andAneilema aequinoctiale (11%), 15 cases by direct observation of 12 individuals of the Mahale M group. At the time of use, we noted behavioral symptoms of illness in the 8 closely observed cases, and detected single or multiple parasitic infections (Strongyloides fulleborni, Trichuris trichiura, Oesophagostomum stephanostomum) in 10 of the 12 individuals. There is a significant relationship between the presence of whole leaves (range, 1–51) and worms of adultO. stephanostomum (range, 2–21) in the dung. HPLC analysis of leaf samples collected after use showed that thiarubrine A, a compound proposed to act as a potent nematocide in swallowingAspilia spp., was not present in leaves ofA. mossambicensis or the three other species analyzed. Alternative nematocidal or egg-laying inhibition activity was not evident. Worms ofO. stephanostomum were recovered live and motile from chimpanzee dung, trapped within the folded leaves and attached to leaf surfaces by trichomes, though some were moving freely within the fecal matter, suggesting that the physical properties of leaves may contribute to the expulsion of parasites. We review previous hypotheses concerning leaf-swallowing and propose an alternative hypothesis based on physical action.
Including genetic considerations in stock enhancement can reduce the probability that enhanced (a... more Including genetic considerations in stock enhancement can reduce the probability that enhanced (admixed) populations will undergo damaging genetic alteration through the stock enhancement effort. Avoiding alterations in genetic diversity, decreases in fitness, and reductions in effective population size (N e ) of admixed populations and their wild-population components is important for the long-term sustainability of those populations. Maintaining the genetic diversity of admixed populations and their wild-population components first requires managing both the genetic variability (e.g., numbers of alleles) and the genetic composition (frequencies of alleles) in the broodstocks and the broods. These genetic diversity components should be maintained at levels appropriate for each stock enhancement program throughout all aspects of stock enhancement—from broodstock selection through the rearing and releasing the broods and then, after release of the broods, in the admixed populations and their wild-population components until the admixed populations attain genetic equilibrium. Using small numbers of broodstock individuals, unequal contributions of broodstock individuals to broods, and inbreeding in broodstocks are common causes of alterations in genetic diversity. These pitfalls should be avoided because they can reduce genetic variability, change genetic composition, and increase genetic load (accumulation of deleterious alleles), which decreases the fitness hatchery broods. In an admixed population, reduction in the fitness of any population component (hatchery, wild, or their progeny) decreases the overall fitness of the admixed population. Hatchery brood fitness can also be reduced through outbreeding, which also ultimately decreases the fitness of the admixed population. Decreases in fitness of admixed populations or of any population components can extend over generations, particularly if stocking is repeated over multiple generations. The N e of a population is directly related to losses in fitness due to inbreeding and reductions in genetic diversity. The smaller the N e value of a population, the greater the chance that relatives will mate and that alleles (particularly rare alleles) will be lost over generations. Genetic monitoring programs for specific stock enhancement efforts should contain sufficient procedures to address all potential genetic concerns. Two types of genetics are used in stock enhancement genetic monitoring programs: population genetics (possibly with some phylogenetics) and diagnostic genetics. Numerous genetic markers are available for use in these programs, including allozyme loci, microsatellite DNA loci, single-nucleotide DNA polymorphisms, and mitochondrial DNA. Genetic tags can be constructed using these markers. The most informative genetic tags enable individuals with alleles derived from hatchery broodstocks to be distinguished in admixed population and also allow the parentage and family relationships of hatchery brood individuals to be identified. A comprehensive genetic monitoring program for stock enhancement should include a baseline population genetics study of the recipient species throughout much or all of its range; genetic identification of all broodstocks at sufficient resolution to distinguish their offspring from wild individuals; genetic monitoring of the broods to compare their genetic diversity components, fitnesses, and N e s with those values for the population into which they will be introduced; and monitoring of the admixed population and its wild-population component during the period of time over which releases occur and after they have occurred. A principal objective of stock enhancement is to improve the probability that wild populations will sustain and be viable over ecological or evolutionary time frames. Managing the genetics of stock enhancement endeavor can increase the probability that this goal will be achieved, as well as improve hatchery production.
Molecular Phylogenetics and Evolution, 1999
Phylogenetic relationships among the 12 recognized fish species in the New World genus Centropomu... more Phylogenetic relationships among the 12 recognized fish species in the New World genus Centropomus (Pisces, Centropomidae) were analyzed using allozyme electrophoresis and 618 bp of the mitochondrial DNA 16S ribosomal RNA (rRNA) gene. Molecular phylogenetic trees were generally consistent with previously published partial hypotheses based on morphological evidence. However, previously undefined sister group relationships between major species groups were resolved using molecular data, and phylogenetic hypotheses for Centropomus based on 16S rRNA sequences were better supported than were allozyme-based hypotheses. The high level of congruence among the trees inferred from the nuclear and mitochondrial characters provided a firm phylogenetic basis for analysis of ecological diversification and molecular evolution in the genus. Compared to basal Centropomus species, members of the most nested species group were significantly larger in body size and occupied a marine niche only peripherally utilized by their congeners. We also observed substitution rate heterogeneity among 16S rRNAlineages; in contrast to expectations based on ''metabolic rate'' and ''generation interval'' models, relative substitution rates were faster than expected for the group of large-bodied snooks. Using the Pliocene rise of the Central American isthmian marine barrier to calibrate rates of 16S ribosomal gene evolution in Centropomus, we found that the rates for the genus were similar to those reported for higher vertebrates. Analysis of the three sets of transisthmian geminate taxa in Centropomus indicated that two of the pairs were probably formed during the Pliocene rise of the isthmus while the third pair diverged several million years earlier. 1999 Academic Press
Transactions of The American Fisheries Society, 1999
The purposes of this study were to evaluate the present species classification, to develop geneti... more The purposes of this study were to evaluate the present species classification, to develop genetic methods for diagnosing morphologically indistinguishable juveniles, and to investigate the potential for introgressive hybridization for species of the percoid fish genus Centropomus (Pisces: Centropomidae). We analyzed specimens representing all nominal species using allozyme electrophoretic data and sequence data from a 618-base-pair portion of the mitochondrial
Molecular Ecology Resources, 2008
Here we describe 18 polymorphic microsatellite loci for Trichechus manatus latirostris (Florida m... more Here we describe 18 polymorphic microsatellite loci for Trichechus manatus latirostris (Florida manatee), isolated using a polymerase chain reaction-based technique. The number of alleles at each locus ranged from two to four (mean = 2.5) in specimens from southwest (n = 58) and northeast (n = 58) Florida. Expected and observed heterozygosities ranged from 0.11 to 0.67 (mean = 0.35) and from 0.02 to 0.78 (mean = 0.34), respectively. Departures from Hardy–Weinberg equilibrium occurred at two loci. There was no evidence of genotypic disequilibrium for any pair of loci. For individual identification, mean random-mating and θ-corrected match probabilities were 9.36 × 10−7 and 1.95 × 10−6, respectively.
Molecular Ecology Notes, 2006
Here we describe 13 polymorphic, dinucleotide microsatellite loci for Trachinotus carolinus (Flor... more Here we describe 13 polymorphic, dinucleotide microsatellite loci for Trachinotus carolinus (Florida pompano), isolated by using PIMA, a polymerase chain reaction-based technique. The number of alleles at each locus ranged from 3 to 29 (mean = 11.4) in 45 specimens collected from bay and nearshore waters around St Petersburg, Florida. Levels of expected and observed heterozygosities ranged from 0.15 to 0.94 (mean = 0.69) and from 0.16 to 0.98 (mean = 0.70), respectively. No significant departures from Hardy–Weinberg equilibrium expectations were observed. In exact tests for genotypic disequilibrium, there was no evidence of linkage for any pair of loci. The ability of these markers to cross-amplify in two congeneric Trachinotus species —T. falcatus (permit) and T. goodei (palometa) — was also assessed. The loci were well-resolved, highly polymorphic, and independently segregating in these taxa, also suggesting a general utility for intraspecific studies, species identification, and investigation of interspecific hybridization.
Reviews in Fisheries Science, 2008
Managers of restocking and stock enhancement programs have dual needs with respect to unit-stock ... more Managers of restocking and stock enhancement programs have dual needs with respect to unit-stock identification: (1) identifying boundaries of genetically discrete stocks for responsible genetic management, and (2) delineating demographically discrete stocks. The reality, however, is that the temporal/spatial boundaries of genetic and demographic stocks may be discordant. Tagging data for the common snook, Centropomus undecimalis, show that there is little movement between Florida (FL) Gulf of Mexico and Atlantic waters. Nearly all snook from the Gulf inhabit a single estuary for their entire lives, whereas most Atlantic snook stray or emigrate much greater distances. A robust microsatellite DNA analysis of > 1,300 specimens confirmed the genetic distinctiveness of Gulf and Atlantic stocks. Curiously, there was no evidence of genetic structure within the Gulf stock. Inferring demographic stock boundaries using genetic data alone could lead to the erroneous conclusion that releases in a single Gulf estuary would eventually influence catch rates along the entire Gulf coast. Alternative methods for unit-stock identification and careful consideration of their inherent limitations are needed to identify the area over which demographic benefits or genetic impacts from releases of cultured juveniles can be expected.
Molecular Ecology Resources, 2008
Twelve polymorphic microsatellite loci were isolated for the bonefish, Albula vulpes using a poly... more Twelve polymorphic microsatellite loci were isolated for the bonefish, Albula vulpes using a polymerase chain reaction-based procedure. The number of alleles ranged from two to 23 (mean = 8.8) in 37 specimens from south Florida. Observed and expected heterozygosities ranged from 0.07 to 0.77 (mean = 0.42) and from 0.07 to 0.84 (mean = 0.48), respectively. There were no significant departures from Hardy–Weinberg equilibrium and no evidence of genotypic disequilibrium between any pair of loci. In a cross-amplification test, all markers yielded appropriately sized alleles for specimens of the provisional Albula sp. B and 11 of the 12 loci amplified for those of Albula glossodonta.
Primates, 1989
Detailed observations on the consumption ofVernonia amygdalina (Del.), a naturally occurring plan... more Detailed observations on the consumption ofVernonia amygdalina (Del.), a naturally occurring plant of known ethnomedicinal value, by an adult female chimpanzee (Pan troglodytes schweinfurthii) of M-group in the Mahale Mountains, Tanzania were made. Chewing the pith of several shoots, she sucked out and swallowed the astringent, bitter tasting juice; spitting out the fibrous remains. The female was followed during this period for 11 hr, over two consecutive days, and was recognized to be in irregular health at the time of consumption, exhibiting signs of lethargy, lack of appetite, and irregularity of bodily excretions. The low frequency and lack of seasonality in the usage of this plant suggest that it is sought after for reasons other than as a food source. These factors suggest that for chimpanzees, the consumption of this plant is primarily medicinal. The symptoms displayed by the female are the same as those experienced by people throughout tropical Africa who utilize this plant as a medicinal treatment for them. Interactions between the female and others suggest that they too were aware of her condition and coordinated their activities with the female and her infant.
Primates, 1993
A 12-year-old female chimpanzee (Pan troglodytes schweinfurthii) of M-Group in the Mahale Mountai... more A 12-year-old female chimpanzee (Pan troglodytes schweinfurthii) of M-Group in the Mahale Mountains National Park, Tanzania was seen to rouse, capture, and eat a squirrel hiding in the narrow hole of a tree. The kill was aided by the use of a sturdy tool modified from a branch of the same tree. This appears to be the first reported case for chimpanzees, or any other nonhuman primate, of tool-use that directly led to the capture of a mammalian prey species. This behavior is discussed in relation to possible factors contributing to the occurrence of tool-use in small mammal predation especially by females to exploit a low competition meat source.
International Journal of Primatology, 1996
Swallowing whole leaves by chimpanzees and other African apes has been hypothesized to have an an... more Swallowing whole leaves by chimpanzees and other African apes has been hypothesized to have an antiparasitic or medicinal function, but detailed studies demonstrating this were lacking. We correlate for the first time quantifiable measures of the health of chimpanzees with observations of leaf-swallowing in Mahale Mountains National Park, Tanzania. We obtained a total of 27 cases involving the use ofAspilia mossambicensis (63%),Lippia plicata (7%),Hibiscus sp. (15%),Trema orientalis (4%), andAneilema aequinoctiale (11%), 15 cases by direct observation of 12 individuals of the Mahale M group. At the time of use, we noted behavioral symptoms of illness in the 8 closely observed cases, and detected single or multiple parasitic infections (Strongyloides fulleborni, Trichuris trichiura, Oesophagostomum stephanostomum) in 10 of the 12 individuals. There is a significant relationship between the presence of whole leaves (range, 1–51) and worms of adultO. stephanostomum (range, 2–21) in the dung. HPLC analysis of leaf samples collected after use showed that thiarubrine A, a compound proposed to act as a potent nematocide in swallowingAspilia spp., was not present in leaves ofA. mossambicensis or the three other species analyzed. Alternative nematocidal or egg-laying inhibition activity was not evident. Worms ofO. stephanostomum were recovered live and motile from chimpanzee dung, trapped within the folded leaves and attached to leaf surfaces by trichomes, though some were moving freely within the fecal matter, suggesting that the physical properties of leaves may contribute to the expulsion of parasites. We review previous hypotheses concerning leaf-swallowing and propose an alternative hypothesis based on physical action.
Including genetic considerations in stock enhancement can reduce the probability that enhanced (a... more Including genetic considerations in stock enhancement can reduce the probability that enhanced (admixed) populations will undergo damaging genetic alteration through the stock enhancement effort. Avoiding alterations in genetic diversity, decreases in fitness, and reductions in effective population size (N e ) of admixed populations and their wild-population components is important for the long-term sustainability of those populations. Maintaining the genetic diversity of admixed populations and their wild-population components first requires managing both the genetic variability (e.g., numbers of alleles) and the genetic composition (frequencies of alleles) in the broodstocks and the broods. These genetic diversity components should be maintained at levels appropriate for each stock enhancement program throughout all aspects of stock enhancement—from broodstock selection through the rearing and releasing the broods and then, after release of the broods, in the admixed populations and their wild-population components until the admixed populations attain genetic equilibrium. Using small numbers of broodstock individuals, unequal contributions of broodstock individuals to broods, and inbreeding in broodstocks are common causes of alterations in genetic diversity. These pitfalls should be avoided because they can reduce genetic variability, change genetic composition, and increase genetic load (accumulation of deleterious alleles), which decreases the fitness hatchery broods. In an admixed population, reduction in the fitness of any population component (hatchery, wild, or their progeny) decreases the overall fitness of the admixed population. Hatchery brood fitness can also be reduced through outbreeding, which also ultimately decreases the fitness of the admixed population. Decreases in fitness of admixed populations or of any population components can extend over generations, particularly if stocking is repeated over multiple generations. The N e of a population is directly related to losses in fitness due to inbreeding and reductions in genetic diversity. The smaller the N e value of a population, the greater the chance that relatives will mate and that alleles (particularly rare alleles) will be lost over generations. Genetic monitoring programs for specific stock enhancement efforts should contain sufficient procedures to address all potential genetic concerns. Two types of genetics are used in stock enhancement genetic monitoring programs: population genetics (possibly with some phylogenetics) and diagnostic genetics. Numerous genetic markers are available for use in these programs, including allozyme loci, microsatellite DNA loci, single-nucleotide DNA polymorphisms, and mitochondrial DNA. Genetic tags can be constructed using these markers. The most informative genetic tags enable individuals with alleles derived from hatchery broodstocks to be distinguished in admixed population and also allow the parentage and family relationships of hatchery brood individuals to be identified. A comprehensive genetic monitoring program for stock enhancement should include a baseline population genetics study of the recipient species throughout much or all of its range; genetic identification of all broodstocks at sufficient resolution to distinguish their offspring from wild individuals; genetic monitoring of the broods to compare their genetic diversity components, fitnesses, and N e s with those values for the population into which they will be introduced; and monitoring of the admixed population and its wild-population component during the period of time over which releases occur and after they have occurred. A principal objective of stock enhancement is to improve the probability that wild populations will sustain and be viable over ecological or evolutionary time frames. Managing the genetics of stock enhancement endeavor can increase the probability that this goal will be achieved, as well as improve hatchery production.
Molecular Phylogenetics and Evolution, 1999
Phylogenetic relationships among the 12 recognized fish species in the New World genus Centropomu... more Phylogenetic relationships among the 12 recognized fish species in the New World genus Centropomus (Pisces, Centropomidae) were analyzed using allozyme electrophoresis and 618 bp of the mitochondrial DNA 16S ribosomal RNA (rRNA) gene. Molecular phylogenetic trees were generally consistent with previously published partial hypotheses based on morphological evidence. However, previously undefined sister group relationships between major species groups were resolved using molecular data, and phylogenetic hypotheses for Centropomus based on 16S rRNA sequences were better supported than were allozyme-based hypotheses. The high level of congruence among the trees inferred from the nuclear and mitochondrial characters provided a firm phylogenetic basis for analysis of ecological diversification and molecular evolution in the genus. Compared to basal Centropomus species, members of the most nested species group were significantly larger in body size and occupied a marine niche only peripherally utilized by their congeners. We also observed substitution rate heterogeneity among 16S rRNAlineages; in contrast to expectations based on ''metabolic rate'' and ''generation interval'' models, relative substitution rates were faster than expected for the group of large-bodied snooks. Using the Pliocene rise of the Central American isthmian marine barrier to calibrate rates of 16S ribosomal gene evolution in Centropomus, we found that the rates for the genus were similar to those reported for higher vertebrates. Analysis of the three sets of transisthmian geminate taxa in Centropomus indicated that two of the pairs were probably formed during the Pliocene rise of the isthmus while the third pair diverged several million years earlier. 1999 Academic Press
Transactions of The American Fisheries Society, 1999
The purposes of this study were to evaluate the present species classification, to develop geneti... more The purposes of this study were to evaluate the present species classification, to develop genetic methods for diagnosing morphologically indistinguishable juveniles, and to investigate the potential for introgressive hybridization for species of the percoid fish genus Centropomus (Pisces: Centropomidae). We analyzed specimens representing all nominal species using allozyme electrophoretic data and sequence data from a 618-base-pair portion of the mitochondrial
Molecular Ecology Resources, 2008
Here we describe 18 polymorphic microsatellite loci for Trichechus manatus latirostris (Florida m... more Here we describe 18 polymorphic microsatellite loci for Trichechus manatus latirostris (Florida manatee), isolated using a polymerase chain reaction-based technique. The number of alleles at each locus ranged from two to four (mean = 2.5) in specimens from southwest (n = 58) and northeast (n = 58) Florida. Expected and observed heterozygosities ranged from 0.11 to 0.67 (mean = 0.35) and from 0.02 to 0.78 (mean = 0.34), respectively. Departures from Hardy–Weinberg equilibrium occurred at two loci. There was no evidence of genotypic disequilibrium for any pair of loci. For individual identification, mean random-mating and θ-corrected match probabilities were 9.36 × 10−7 and 1.95 × 10−6, respectively.
Molecular Ecology Notes, 2006
Here we describe 13 polymorphic, dinucleotide microsatellite loci for Trachinotus carolinus (Flor... more Here we describe 13 polymorphic, dinucleotide microsatellite loci for Trachinotus carolinus (Florida pompano), isolated by using PIMA, a polymerase chain reaction-based technique. The number of alleles at each locus ranged from 3 to 29 (mean = 11.4) in 45 specimens collected from bay and nearshore waters around St Petersburg, Florida. Levels of expected and observed heterozygosities ranged from 0.15 to 0.94 (mean = 0.69) and from 0.16 to 0.98 (mean = 0.70), respectively. No significant departures from Hardy–Weinberg equilibrium expectations were observed. In exact tests for genotypic disequilibrium, there was no evidence of linkage for any pair of loci. The ability of these markers to cross-amplify in two congeneric Trachinotus species —T. falcatus (permit) and T. goodei (palometa) — was also assessed. The loci were well-resolved, highly polymorphic, and independently segregating in these taxa, also suggesting a general utility for intraspecific studies, species identification, and investigation of interspecific hybridization.
Reviews in Fisheries Science, 2008
Managers of restocking and stock enhancement programs have dual needs with respect to unit-stock ... more Managers of restocking and stock enhancement programs have dual needs with respect to unit-stock identification: (1) identifying boundaries of genetically discrete stocks for responsible genetic management, and (2) delineating demographically discrete stocks. The reality, however, is that the temporal/spatial boundaries of genetic and demographic stocks may be discordant. Tagging data for the common snook, Centropomus undecimalis, show that there is little movement between Florida (FL) Gulf of Mexico and Atlantic waters. Nearly all snook from the Gulf inhabit a single estuary for their entire lives, whereas most Atlantic snook stray or emigrate much greater distances. A robust microsatellite DNA analysis of > 1,300 specimens confirmed the genetic distinctiveness of Gulf and Atlantic stocks. Curiously, there was no evidence of genetic structure within the Gulf stock. Inferring demographic stock boundaries using genetic data alone could lead to the erroneous conclusion that releases in a single Gulf estuary would eventually influence catch rates along the entire Gulf coast. Alternative methods for unit-stock identification and careful consideration of their inherent limitations are needed to identify the area over which demographic benefits or genetic impacts from releases of cultured juveniles can be expected.
Molecular Ecology Resources, 2008
Twelve polymorphic microsatellite loci were isolated for the bonefish, Albula vulpes using a poly... more Twelve polymorphic microsatellite loci were isolated for the bonefish, Albula vulpes using a polymerase chain reaction-based procedure. The number of alleles ranged from two to 23 (mean = 8.8) in 37 specimens from south Florida. Observed and expected heterozygosities ranged from 0.07 to 0.77 (mean = 0.42) and from 0.07 to 0.84 (mean = 0.48), respectively. There were no significant departures from Hardy–Weinberg equilibrium and no evidence of genotypic disequilibrium between any pair of loci. In a cross-amplification test, all markers yielded appropriately sized alleles for specimens of the provisional Albula sp. B and 11 of the 12 loci amplified for those of Albula glossodonta.
Primates, 1989
Detailed observations on the consumption ofVernonia amygdalina (Del.), a naturally occurring plan... more Detailed observations on the consumption ofVernonia amygdalina (Del.), a naturally occurring plant of known ethnomedicinal value, by an adult female chimpanzee (Pan troglodytes schweinfurthii) of M-group in the Mahale Mountains, Tanzania were made. Chewing the pith of several shoots, she sucked out and swallowed the astringent, bitter tasting juice; spitting out the fibrous remains. The female was followed during this period for 11 hr, over two consecutive days, and was recognized to be in irregular health at the time of consumption, exhibiting signs of lethargy, lack of appetite, and irregularity of bodily excretions. The low frequency and lack of seasonality in the usage of this plant suggest that it is sought after for reasons other than as a food source. These factors suggest that for chimpanzees, the consumption of this plant is primarily medicinal. The symptoms displayed by the female are the same as those experienced by people throughout tropical Africa who utilize this plant as a medicinal treatment for them. Interactions between the female and others suggest that they too were aware of her condition and coordinated their activities with the female and her infant.