Genetics / DNA
Archie, E., C. Moss, and S. Alberts (2003). Characterization of tetranucleotide microsatellite loci in the African savannah elephant (Loxodonta africana africana). Molecular Ecology Notes 3(2): 244-246. ISSN: 1471-8278.
NAL Call Number: QH541.15.M632
Descriptors: African elephants, population genetics, molecular genetics, microsatellite loci characterization, tetranucleotide microsatellite locus.
Charif, R.A., R.R. Ramey, W.R. Langbauer, K.B. Payne, R.B. Martin, and L.M. Brown (2005). Spatial relationships and matrilineal kinship in African savanna elephant (Loxodonta africana) clans. Behavioral Ecology and Sociobiology 57(4): 327-338. ISSN: 0340-5443.
NAL Call Number: QL751.B4
Descriptors: African elephant, Loxodonta africana, spatial relationships, molecular genetics, mtdna, haplotypes, clans, home range, distribution, matrilineal kinship.
Comstock, K.E., E.A. Ostrander, and S.K. Wasser (2003). Amplifying nuclear and mitochondrial DNA from African elephant ivory: a tool for monitoring the ivory trade. Conservation Biology: 1840-1843.
NAL Call Number: QH75.A2C5
Descriptors: elephant ivory trade, mitochondrial DNA, tool, monitoring, genetic method, pulverized ivory, DNA, antipoaching efforts, forensic analysis.
Debruyne, R. (2004). Apports de la phylogenie moleculaire et de la morphometrie a la systematique des elephants d'Afrique. [Contribution of molecular phylogeny and morphometrics to the systematics of African elephants]. Journal De La Societe De Biologie 198(4): 335-342.
NAL Call Number: QH301.S6
Abstract: African elephants are conventionally classified as a single species: Loxodonta africana (Blumenbach 1797). However, the discovery in 1900 of a smaller form of the African elephant, spread throughout the equatorial belt of this land, has given rise to a debate over the relevance of a second species of elephant in Africa. The twentieth century has not provided any definite answer to this question. Actually, recent molecular analyses have sustained this issue by advocating either a division of forest elephants into a valid species, or their inclusion as a subspecies of L. africana. Our work initiated at the National Museum of Natural History of Paris provides new molecular (mitochondrial) and morphological (and morphometrical) evidence making it possible to propose a comprehensive phylogenetic hypothesis. It appears that there is no conclusive argument to keep forest elephants (cyclotis form) and savannah elephants (africana form) apart in two distinct species. A high level of mitochondrial introgression between the two forms, as well as a continuum in the morphology of the skulls of the two morphotypes rather suggests that, despite an ancient division, these two taxa freely interbreed wherever their ranges intersect. We thus adopt a conservative systematic position in considering these two forms as two subspecies, respectively: L. africana africana, the savannah elephant, and L. africana cyclotis, the forest elephant. We finally discuss the conservation topic in the light of this systematic framework.
Descriptors: classification, genetics, molecular evolution, phylogeny, Africa, body size, mitochondrial DNA genetics, anatomy and histology, museums, skull anatomy and histology.
Language of Text: French.
Lei, R., R.A. Brenneman, and E.E.J. Louis (2008). Genetic diversity in the North American captive African elephant collection. Journal of Zoology 275(3): 252-267. ISSN: 0952-8369.
Descriptors: African elephant, Loxodonta africana, genetic diversity, genotypes, heterozygosity, microsatellites, mitochondrial DNA, nucleotide sequences, zoo animals.
Nyakaana, S., J.B. Okello, V. Muwanika, and H.R. Siegismund (2005). Six new polymorphic microsatellite loci isolated and characterized from the African savannah elephant genome. Molecular Ecology Notes 5(2): 223-225. ISSN: 1471-8278.
NAL Call Number: QH541.15.M632
Descriptors: African elephant, savannah, polymorphic microsatellite loci, genome, polymerase chain reaction, PCR, screening, isolation, characterization, markers.
Okello, J.B., G. Wittemyer, H.B. Rasmussen, I. Douglas Hamilton, S. Nyakaana, P. Arctander, and H.R. Siegismund (2005). Noninvasive genotyping and Mendelian analysis of microsatellites in African savannah elephants. Journal of Heredity 96(6): 679-87.
NAL Call Number: 442.8 Am3
Abstract: We obtained fresh dung samples from 202 (133 mother-offspring pairs) savannah elephants (Loxodonta africana) in Samburu, Kenya, and genotyped them at 20 microsatellite loci to assess genotyping success and errors. A total of 98.6% consensus genotypes was successfully obtained, with allelic dropout and false allele rates at 1.6% (n = 46) and 0.9% (n = 37) of heterozygous and total consensus genotypes, respectively, and an overall genotyping error rate of 2.5% based on repeat typing. Mendelian analysis revealed consistent inheritance in all but 38 allelic pairs from mother-offspring, giving an average mismatch error rate of 2.06%, a possible result of null alleles, mutations, genotyping errors, or inaccuracy in maternity assignment. We detected no evidence for large allele dropout, stuttering, or scoring error in the dataset and significant Hardy-Weinberg deviations at only two loci due to heterozygosity deficiency. Across loci, null allele frequencies were low (range: 0.000-0.042) and below the 0.20 threshold that would significantly bias individual-based studies. The high genotyping success and low errors observed in this study demonstrate reliability of the method employed and underscore the application of simple pedigrees in noninvasive studies. Since none of the sires were included in this study, the error rates presented are just estimates.
Descriptors: DNA analysis, genetics, feces chemistry, genetic techniques, microsatellite repeats genetics, genotype, Kenya, polymerase chain reaction methods.
Rautian, G.S. and I.A. Dubrovo (2003). Data on DNA give evidence for parallel development in mammoths and elephants. Deinsea 9: 381-394. ISSN: 0923-9308.
Descriptors: Elephas maximus, Loxodonta africana, Mammuthus primigenius, Elephantidae, Mammut americanus, Mammutidae, nucleic acids, molecular genetics, DNA, parallel evolution, genetic data, phylogeny.
Roca, A.L., N. Georgiadis, and S.J. O'Brien (2005). Cytonuclear genomic dissociation in African elephant species. Nature Genetics 37(1): 96-100.
NAL Call Number: QH426.N37
Abstract: African forest and savanna elephants are distinct species separated by a hybrid zone. Because hybridization can affect the systematic and conservation status of populations, we examined gene flow between forest and savanna elephants at 21 African locations. We detected cytonuclear dissociation, indicative of different evolutionary histories for nuclear and mitochondrial genomes. Both paternally (n = 205 males) and biparentally (n = 2,123 X-chromosome segments) inherited gene sequences indicated that there was deep genetic separation between forest and savanna elephants. Yet in some savanna locales distant from present-day forest habitats, many individuals with savanna-specific nuclear genotypes carried maternally transmitted forest elephant mitochondrial DNA. This extreme cytonuclear dissociation implies that there were ancient episodes of hybridization between forest females and savanna males, which are larger and reproductively dominant to forest or hybrid males. Recurrent backcrossing of female hybrids to savanna bulls replaced the forest nuclear genome. The persistence of residual forest elephant mitochondria in savanna elephant herds renders evolutionary interpretations based on mitochondrial DNA alone misleading and preserves a genomic record of ancient habitat changes.
Descriptors: genetics, gene frequency, population genetics, Africa south of the Sahara, mitochondrial DNA, haplotypes, molecular sequence data, phylogeny.
Roca, A.L. and S.J. O'Brien (2005). Genomic inferences from Afrotheria and the evolution of elephants. Current Opinion in Genetics and Development 15(6): 652-659.
NAL Call Number: QH426.C88
Abstract: Recent genetic studies have established that African forest and savanna elephants are distinct species with dissociated cytonuclear genomic patterns, and have identified Asian elephants from Borneo and Sumatra as conservation priorities. Representative of Afrotheria, a superordinal clade encompassing six eutherian orders, the African savanna elephant was among the first mammals chosen for whole-genome sequencing to provide a comparative understanding of the human genome. Elephants have large and complex brains and display advanced levels of social structure, communication, learning and intelligence. The elephant genome sequence might prove useful for comparative genomic studies of these advanced traits, which have appeared independently in only three mammalian orders: primates, cetaceans and proboscideans.
Descriptors: evolution, genetics, DNA, African elephants, Asian elephants, genomic patterns.
Wasser, S.K., W.J. Clark, O. Drori, E.S. Kisamo, C. Mailand, B. Mutayoba, and M. Stephens (2008). Combating the illegal trade in African elephant ivory with DNA forensics. Conservation Biology 22(4): 1065-1071. ISSN: 0888-8892.
Descriptors: African elephants, Loxodonta africana, wildlife crime, DNA, forensic science, trade in animals, conservation.
Language of Text: Summaries in English and Spanish.
Wasser, S.K., A.M. Shedlock, K. Comstock, E.A. Ostrander, B. Mutayoba, and M. Stephens (2004). Assigning African elephant DNA to geographic region of origin: applications to the ivory trade. Proceedings of the National Academy of Sciences of the United States of America 101(41): 14847-14852.
NAL Call Number: 500 N31P
Abstract: Resurgence of illicit trade in African elephant ivory is placing the elephant at renewed risk. Regulation of this trade could be vastly improved by the ability to verify the geographic origin of tusks. We address this need by developing a combined genetic and statistical method to determine the origin of poached ivory. Our statistical approach exploits a smoothing method to estimate geographic-specific allele frequencies over the entire African elephants' range for 16 microsatellite loci, using 315 tissue and 84 scat samples from forest (Loxodonta africana cyclotis) and savannah (Loxodonta africana africana) elephants at 28 locations. These geographic-specific allele frequency estimates are used to infer the geographic origin of DNA samples, such as could be obtained from tusks of unknown origin. We demonstrate that our method alleviates several problems associated with standard assignment methods in this context, and the absolute accuracy of our method is high. Continent-wide, 50% of samples were located within 500 km, and 80% within 932 km of their actual place of origin. Accuracy varied by region (median accuracies: West Africa, 135 km; Central Savannah, 286 km; Central Forest, 411 km; South, 535 km; and East, 697 km). In some cases, allele frequencies vary considerably over small geographic regions, making much finer discriminations possible and suggesting that resolution could be further improved by collection of samples from locations not represented in our study.
Descriptors: DNA genetics, dentin chemistry, Africa, geography, microsatellite repeats.