ABSTRACT
The development of a linkage map is an important component for promoting genetic and genomic studies in California condors, an endangered New World vulture species. Using a set of designed anonymous microsatellite markers, we genotyped a reference condor population involving 121 individuals. After marker validation and genotype filtering, the genetic linkage analysis was performed using 123 microsatellite loci. This resulted in the identification of 15 linkage groups/subgroups that formed a first-generation condor genetic map, while no markers linked to a lethal chondrodystrophy mutation were found. A panel of polymorphic markers that is instrumental in molecular parentage diagnostics and other genetic studies in the California condor was selected. Further condor conservation genomics research will be focused on updating the linkage map and integrating it with cytogenetic and BAC-based physical maps and ultimately with the genome sequence assembly.
ABSTRACT
Parthenogenesis is a relatively rare event in birds, documented in unfertilized eggs from columbid, galliform, and passerine females with no access to males. In the critically endangered California condor, parentage analysis conducted utilizing polymorphic microsatellite loci has identified two instances of parthenogenetic development from the eggs of two females in the captive breeding program, each continuously housed with a reproductively capable male with whom they had produced offspring. Paternal genetic contribution to the two chicks was excluded. Both parthenotes possessed the expected male ZZ sex chromosomes and were homozygous for all evaluated markers inherited from their dams. These findings represent the first molecular marker-based identification of facultative parthenogenesis in an avian species, notably of females in regular contact with fertile males, and add to the phylogenetic breadth of vertebrate taxa documented to have reproduced via asexual reproduction.
Subject(s)
Fertility , Parthenogenesis , Female , Homozygote , Humans , Male , Parthenogenesis/genetics , PhylogenyABSTRACT
BACKGROUND: The Masai giraffe (Giraffa camelopardalis tippelskirchi) is the largest-bodied giraffe and the world's tallest terrestrial animal. With its extreme size and height, the giraffe's unique anatomical and physiological adaptations have long been of interest to diverse research fields. Giraffes are also critical to ecosystems of sub-Saharan Africa, with their long neck serving as a conduit to food sources not shared by other herbivores. Although the genome of a Masai giraffe has been sequenced, the assembly was highly fragmented and suboptimal for genome analysis. Herein we report an improved giraffe genome assembly to facilitate evolutionary analysis of the giraffe and other ruminant genomes. FINDINGS: Using SOAPdenovo2 and 170 Gbp of Illumina paired-end and mate-pair reads, we generated a 2.6-Gbp male Masai giraffe genome assembly, with a scaffold N50 of 3 Mbp. The incorporation of 114.6 Gbp of Chicago library sequencing data resulted in a HiRise SOAPdenovo + Chicago assembly with an N50 of 48 Mbp and containing 95% of expected genes according to BUSCO analysis. Using the Reference-Assisted Chromosome Assembly tool, we were able to order and orient scaffolds into 42 predicted chromosome fragments (PCFs). Using fluorescence in situ hybridization, we placed 153 cattle bacterial artificial chromosomes onto giraffe metaphase spreads to assess and assign the PCFs on 14 giraffe autosomes and the X chromosome resulting in the final assembly with an N50 of 177.94 Mbp. In this assembly, 21,621 protein-coding genes were identified using both de novo and homology-based predictions. CONCLUSIONS: We have produced the first chromosome-scale genome assembly for a Giraffidae species. This assembly provides a valuable resource for the study of artiodactyl evolution and for understanding the molecular basis of the unique adaptive traits of giraffes. In addition, the assembly will provide a powerful resource to assist conservation efforts of Masai giraffe, whose population size has declined by 52% in recent years.
Subject(s)
Chromosomes, Mammalian , Genome , Genomics , Giraffes/genetics , Animals , Computational Biology/methods , Evolution, Molecular , Genomics/methods , High-Throughput Nucleotide Sequencing , Karyotyping , Molecular Sequence Annotation , PhylogenyABSTRACT
The ruminants are one of the most successful mammalian lineages, exhibiting morphological and habitat diversity and containing several key livestock species. To better understand their evolution, we generated and analyzed de novo assembled genomes of 44 ruminant species, representing all six Ruminantia families. We used these genomes to create a time-calibrated phylogeny to resolve topological controversies, overcoming the challenges of incomplete lineage sorting. Population dynamic analyses show that population declines commenced between 100,000 and 50,000 years ago, which is concomitant with expansion in human populations. We also reveal genes and regulatory elements that possibly contribute to the evolution of the digestive system, cranial appendages, immune system, metabolism, body size, cursorial locomotion, and dentition of the ruminants.
Subject(s)
Genome , Ruminants/classification , Ruminants/genetics , Animals , Evolution, Molecular , Phylogeny , Sequence Analysis, DNAABSTRACT
Genome-wide assessment of genetic diversity has the potential to increase the ability to understand admixture, inbreeding, kinship and erosion of genetic diversity affecting both captive (ex situ) and wild (in situ) populations of threatened species. The sable antelope (Hippotragus niger), native to the savannah woodlands of sub-Saharan Africa, is a species that is being managed ex situ in both public (zoo) and private (ranch) collections in the United States. Our objective was to develop whole genome sequence resources that will serve as a foundation for characterizing the genetic status of ex situ populations of sable antelope relative to populations in the wild. Here we report the draft genome assembly of a male sable antelope, a member of the subfamily Hippotraginae (Bovidae, Cetartiodactyla, Mammalia). The 2.596 Gb draft genome consists of 136,528 contigs with an N50 of 45.5 Kbp and 16,927 scaffolds with an N50 of 4.59 Mbp. De novo annotation identified 18,828 protein-coding genes and repetitive sequences encompassing 46.97% of the genome. The discovery of single nucleotide variants (SNVs) was assisted by the re-sequencing of seven additional captive and wild individuals, representing two different subspecies, leading to the identification of 1,987,710 bi-allelic SNVs. Assembly of the mitochondrial genomes revealed that each individual was defined by a unique haplotype and these data were used to infer the mitochondrial gene tree relative to other hippotragine species. The sable antelope genome constitutes a valuable resource for assessing genome-wide diversity and evolutionary potential, thereby facilitating long-term conservation of this charismatic species.
Subject(s)
Antelopes/genetics , Genome , Genomics , Whole Genome Sequencing , Animals , Antelopes/classification , Biodiversity , Biological Evolution , Computational Biology/methods , Female , Genetic Variation , Genetics, Population , Genome, Mitochondrial , Genomics/methods , Male , Molecular Sequence Annotation , Phenotype , Phylogeny , United StatesABSTRACT
Background: The gemsbok (Oryx gazella) is one of the largest antelopes in Africa. Gemsbok are heterothermic and thus highly adapted to live in the desert, changing their feeding behavior when faced with extreme drought and heat. A high-quality genome sequence of this species will assist efforts to elucidate these and other important traits of gemsbok and facilitate research on conservation efforts. Findings: Using 180 Gbp of Illumina paired-end and mate-pair reads, a 2.9 Gbp assembly with scaffold N50 of 1.48 Mbp was generated using SOAPdenovo. Scaffolds were extended using Chicago library sequencing, which yielded an additional 114.7 Gbp of DNA sequence. The HiRise assembly using SOAPdenovo + Chicago library sequencing produced a scaffold N50 of 47 Mbp and a final genome size of 2.9 Gbp, representing 90.6% of the estimated genome size and including 93.2% of expected genes according to Benchmarking Universal Single-Copy Orthologs analysis. The Reference-Assisted Chromosome Assembly tool was used to generate a final set of 47 predicted chromosome fragments with N50 of 86.25 Mbp and containing 93.8% of expected genes. A total of 23,125 protein-coding genes and 1.14 Gbp of repetitive sequences were annotated using de novo and homology-based predictions. Conclusions: Our results provide the first high-quality, chromosome-scale genome sequence assembly for gemsbok, which will be a valuable resource for studying adaptive evolution of this species and other ruminants.
Subject(s)
Antelopes/genetics , Genome , Animals , Female , Genomics , High-Throughput Nucleotide Sequencing , Molecular Sequence Annotation , Phylogeny , Sequence Analysis, DNAABSTRACT
Background: Milu, also known as Père David's deer (Elaphurus davidianus), was widely distributed in East Asia but recently experienced a severe bottleneck. Only 18 survived by the end of the 19th century, and the current population of 4500 individuals was propagated from just 11 kept by the 11th British Duke of Bedford. This species is known for its distinguishable appearance, the driving force behind which is still a mystery. To aid efforts to explore these phenomena, we constructed a draft genome of the species. Findings: In total, we generated 321.86 gigabases (Gb) of raw DNA sequence from whole-genome sequencing of a male milu deer using an Illumina HiSeq 2000 platform. Assembly yielded a final genome with a scaffold N50 size of 3.03 megabases (Mb) and a total length of 2.52 Gb. Moreover, we identified 20 125 protein-coding genes and 988.1 Mb of repetitive sequences. In addition, homology-based searches detected 280 rRNA, 1335 miRNA, 1441 snRNA, and 893 tRNA sequences in the milu genome. The divergence time between E. davidianus and Bos taurus was estimated to be about 28.20 million years ago (Mya). We identified 167 species-specific genes and 293 expanded gene families in the milu lineage. Conclusions: We report the first reference genome of milu, which will provide a valuable resource for studying the species' demographic history of severe bottleneck and the genetic mechanism(s) of special phenotypic evolution.
Subject(s)
Biological Evolution , Chromosome Mapping/methods , Deer/genetics , Genome , High-Throughput Nucleotide Sequencing , Animals , Cattle , Deer/classification , Male , MicroRNAs/classification , MicroRNAs/genetics , Open Reading Frames , Phylogeny , Proteins/classification , Proteins/genetics , RNA, Ribosomal/classification , RNA, Ribosomal/genetics , RNA, Small Nuclear/classification , RNA, Small Nuclear/genetics , RNA, Transfer/classification , RNA, Transfer/genetics , Whole Genome SequencingABSTRACT
The monophyletic group Caniformia (dog-like carnivores) in the order Carnivora comprises 9 families. Except for the general consensus for the earliest divergence of Canidae and the grouping of Procyonidae and Mustelidae, conflicting phylogenetic hypotheses exist for the other caniformian families. In the present study, a data set comprising > 22 kb of 22 nuclear intron loci from 16 caniformian species is used to investigate the phylogenetic utility of nuclear introns in resolving the interfamilial relationships of Caniformia. Our phylogenetic analyses support Ailuridae as the sister taxon to a clade containing Procyonidae and Mustelidae, with Mephitinae being the sister taxon to all of them. The unresolved placements of Ursidae and Pinnipeds here emphasize a need to add more data and include more taxa to resolve this problem. The present study not only resolves some of the ambiguous relationships in Caniformia phylogeny but also shows that the noncoding nuclear markers can offer powerful complementary data for estimating the species tree. None of the newly developed introns here have previously been used for phylogeny reconstruction, thus increasing the spectrum of molecular markers available to mammalian systematics. Interestingly, all the newly developed intron data partitions exhibit intraindividual allele heterozygotes (IIAHs). There are 115 cases of IIAHs in total. The incorporation of IIAHs into phylogenetic analysis not only provides insights into the interfamilial relationships of Caniformia but also identifies two potential hybridization events occurred within Ursidae and Otariidae, respectively. Finally, the powers and pitfalls of phylogenetics using nuclear introns as markers are discussed in the context of Caniformia phylogeny.
Subject(s)
Carnivora/classification , Carnivora/genetics , Cell Nucleus/genetics , Introns , Phylogeny , Animals , Heterozygote , HumansABSTRACT
BACKGROUND: Genomic studies in non-domestic avian models, such as the California condor and white-throated sparrow, can lead to more comprehensive conservation plans and provide clues for understanding mechanisms affecting genetic variation, adaptation and evolution.Developing genomic tools and resources including genomic libraries and a genetic map of the California condor is a prerequisite for identification of candidate loci for a heritable embryonic lethal condition. The white-throated sparrow exhibits a stable genetic polymorphism (i.e. chromosomal rearrangements) associated with variation in morphology, physiology, and behavior (e.g., aggression, social behavior, sexual behavior, parental care).In this paper we outline the utility of these species as well as report on recent advances in the study of their genomes. RESULTS: Genotyping of the condor resource population at 17 microsatellite loci provided a better assessment of the current population's genetic variation. Specific New World vulture repeats were found in the condor genome. Using condor BAC library and clones, chicken-condor comparative maps were generated. A condor fibroblast cell line transcriptome was characterized using the 454 sequencing technology.Our karyotypic analyses of the sparrow in combination with other studies indicate that the rearrangements in both chromosomes 2m and 3a are complex and likely involve multiple inversions, interchromosomal linkage, and pleiotropy. At least a portion of the rearrangement in chromosome 2m existed in the common ancestor of the four North American species of Zonotrichia, but not in the one South American species, and that the 2m form, originally thought to be the derived condition, might actually be the ancestral one. CONCLUSION: Mining and characterization of candidate loci in the California condor using molecular genetic and genomic techniques as well as linkage and comparative genomic mapping will eventually enable the identification of carriers of the chondrodystrophy allele, resulting in improved genetic management of this disease.In the white-throated sparrow, genomic studies, combined with ecological data, will help elucidate the basis of genic selection in a natural population. Morphs of the sparrow provide us with a unique opportunity to study intraspecific genomic differences, which have resulted from two separate yet linked evolutionary trajectories. Such results can transform our understanding of evolutionary and conservation biology.
Subject(s)
Conservation of Natural Resources , Genomics , Raptors/genetics , Sparrows/genetics , Animals , Chromosomes, Artificial, Bacterial , Evolution, Molecular , Female , Gene Library , Genetic Linkage , Genetic Variation , Genetics, Population , Karyotyping , Microsatellite Repeats , Sequence Analysis, DNAABSTRACT
Despite their ability to interbreed and produce fertile offspring, there is continued disagreement about the genetic relationship of the domestic horse (Equus caballus) to its endangered wild relative, Przewalski's horse (Equus przewalskii). Analyses have differed as to whether or not Przewalski's horse is placed phylogenetically as a separate sister group to domestic horses. Because Przewalski's horse and domestic horse are so closely related, genetic data can also be used to infer domestication-specific differences between the two. To investigate the genetic relationship of Przewalski's horse to the domestic horse and to address whether evolution of the domestic horse is driven by males or females, five homologous introns (a total of approximately 3 kb) were sequenced on the X and Y chromosomes in two Przewalski's horses and three breeds of domestic horses: Arabian horse, Mongolian domestic horse, and Dartmoor pony. Five autosomal introns (a total of approximately 6 kb) were sequenced for these horses as well. The sequences of sex chromosomal and autosomal introns were used to determine nucleotide diversity and the forces driving evolution in these species. As a result, X chromosomal and autosomal data do not place Przewalski's horses in a separate clade within phylogenetic trees for horses, suggesting a close relationship between domestic and Przewalski's horses. It was also found that there was a lack of nucleotide diversity on the Y chromosome and higher nucleotide diversity than expected on the X chromosome in domestic horses as compared with the Y chromosome and autosomes. This supports the hypothesis that very few male horses along with numerous female horses founded the various domestic horse breeds. Patterns of nucleotide diversity among different types of chromosomes were distinct for Przewalski's in contrast to domestic horses, supporting unique evolutionary histories of the two species.
Subject(s)
Biological Evolution , Chromosomes, Mammalian , Horses/genetics , Sex Chromosomes , Animals , Animals, Domestic , Female , Introns , Male , PhylogenyABSTRACT
Twenty-three polymorphic microsatellite markers were identified and characterized for Cyclura pinguis, a critically endangered species of lizard (Sauria: Iguanidae) native to Anegada Island in the British Virgin Islands. We examined variation at these loci for 39 C. pinguis, finding up to five alleles per locus and an average expected heterozygosity of 0.55. Allele frequency estimates for these microsatellite loci will be used to characterize genetic diversity of captive and wild C. pinguis populations and to estimate relatedness among adult iguanas at the San Diego Zoo that form the nucleus of a captive breeding programme for this critically endangered species.
ABSTRACT
Mustelidae is the largest and most diverse family in the order Carnivora. The phylogenetic relationships among the subfamilies have especially long been a focus of study. Herein we are among the first to employ two new introns (4 and 7) of the nuclear beta-fibrinogen gene to clarify these enigmatic problems. In addition, two previously available nuclear (IRBP exon 1 and TTR intron 1) and one mt (ND2) data sets were also combined and analyzed simultaneously with the newly obtained sequence data in this study. Detailed characterizations of the two intronic regions not only reveal the remarkable occurrences of short interspersed element (SINE) insertion events, providing a new example supporting the attractive hypothesis that attrition of an earlier retroposition may offer a proper environment for successive retropositions by forming a "dimer-like" structure, but also demonstrate their utility in the resolution of mustelid phylogeny. All of our analyses confirm the assemblage of Mustelinae, Lutrinae, and Melinae with confidence; moreover, two clades within Mustelinae were clearly recognized, i.e., genera Mustela and Martes. Notably, genus Martes of Mustelinae was found to branch off first, followed by Melinae and then a clade containing Lutrinae and genus Mustela of Mustelinae, indicating paraphyly of Mustelinae. In addition, Mephitinae diverges before the other mustelids and the monophyletic Procyonidae in all cases, supporting its elevation to a separate family. Additional independent genetic markers are still in need to resolve the trichotomy among Mephitinae and the other two carnivoran clades, Ailuridae and Procyonidae/non-mephitine Mustelidae.
Subject(s)
Evolution, Molecular , Fibrinogen/genetics , Introns/genetics , Mustelidae/genetics , Phylogeny , Animals , Base Sequence , Bayes Theorem , Likelihood Functions , Models, Genetic , Molecular Sequence Data , Mustelidae/classification , Sequence Analysis, DNA , Short Interspersed Nucleotide Elements/geneticsABSTRACT
Sonic Hedgehog (SHH) is one of the most intensively studied genes in developmental biology. It is a highly conserved gene, found in species as diverse as arthropods and mammals. The mammalian SHH encodes a signaling molecule that plays a central role in developmental patterning, especially of the nervous system and the skeletal system. Here, we show that the molecular evolution of SHH is markedly accelerated in primates relative to other mammals. We further show that within primates, the acceleration is most prominent along the lineage leading to humans. Finally, we show that the acceleration in the lineage leading to humans is coupled with signatures of adaptive evolution. In particular, the lineage leading to humans is characterized by a rampant and statistically highly non-random gain of serines and threonines, residues that are potential substrates of post-translational modifications. This suggests that SHH might have evolved more complex post-translational regulation in the lineage leading to humans. Collectively, these findings implicate SHH as a potential contributor to the evolution of primate- or human-specific morphological traits in the nervous and/or skeletal systems and provide the impetus for additional studies aimed at identifying the primate- or human-specific functions of this key development gene.
Subject(s)
Evolution, Molecular , Primates/genetics , Trans-Activators/genetics , Animals , Gene Expression Regulation, Developmental , Genetic Variation , Hedgehog Proteins , Humans , Models, Genetic , Phylogeny , Polymorphism, GeneticABSTRACT
SINEs (Short INterspersed Elements) are a class of non-autonomous mobile elements that are <500 bp in length and have no open reading frames. Individual SINE elements are essentially homoplasy free with known ancestral states, making them useful genetic systems for phylogenetic studies. Alu elements are the most successful SINE in primate genomes and have been utilized for resolving primate phylogenetic relationships and human population genetics. However, no Alu based phylogenetic analysis has yet been performed to resolve relationships among Old World monkeys. Using both a computational approach and polymerase chain reaction display methodology, we identified 285 new Alu insertions from sixteen Old World monkey taxa that were informative at various levels of catarrhine phylogeny. We have utilized these elements along with 12 previously reported loci to construct a phylogenetic tree of the selected taxa. Relationships among all major clades are in general agreement with other molecular and morphological data sets but have stronger statistical support.
Subject(s)
Cercopithecidae/genetics , Phylogeny , Alu Elements/genetics , Animals , Base Sequence , DNA Primers , Likelihood Functions , Models, Genetic , Molecular Sequence Data , Sequence Analysis, DNAABSTRACT
Short INterspersed Elements (SINEs) make very useful phylogenetic markers because the integration of a particular element at a location in the genome is irreversible and of known polarity. These attributes make analysis of SINEs as phylogenetic characters an essentially homoplasy-free affair. Alu elements are primate-specific SINEs that make up a large portion of the human genome and are also widespread in other primates. Using a combination wet-bench and computational approach we recovered 190 Alu insertions, 183 of which are specific to the genomes of nine New World primates. We used these loci to investigate branching order and have produced a cladogram that supports a sister relationship between Atelidae (spider, woolly, and howler monkeys) and Cebidae (marmosets, tamarins, and owl monkeys) and then the joining of this two family clade to Pitheciidae (titi and saki monkeys). The data support these relationships with a homoplasy index of 0.00. In this study, we report one of the largest applications of SINE elements to phylogenetic analysis to date, and the results provide a robust molecular phylogeny for platyrrhine primates.
Subject(s)
Alu Elements , Cebidae/genetics , Phylogeny , Animals , Base Sequence , DNA Primers , Humans , Polymerase Chain ReactionABSTRACT
The human nuclear gene for the catalytic subunit of mitochondrial DNA polymerase gamma ( POLG) contains within its coding region a CAG microsatellite encoding a polyglutamine repeat. Previous studies demonstrated an association between length variation at this repeat and male infertility, suggesting a mechanism whereby the prevalent (CAG)(10) allele, which occurs at a frequency of >80% in different populations, could be maintained by selection. Sequence analysis of the POLG CAG microsatellite region of more than 1000 human chromosomes reveals that virtually all allelic variation at the locus is accounted for by length variation of the CAG repeat. Analysis of POLG from African great apes shows that a prevalent length allele is present in each species, although its exact length is species-specific. In common chimpanzee ( Pan troglodytes) a number of different sequence variants contribute to the prevalent length allele, strongly supporting the idea that the length of the POLG microsatellite region, rather than its exact nucleotide or amino acid sequence, is what is maintained. Analysis of POLG in other primates indicates that the repeat has expanded from a shorter, glutamine-rich sequence, present in the common ancestor of Old and New World monkeys.
Subject(s)
DNA-Directed DNA Polymerase/genetics , Hominidae/genetics , Trinucleotide Repeats , Amino Acid Sequence , Animals , Base Sequence , DNA Polymerase gamma , Haplorhini/genetics , Humans , Molecular Sequence DataABSTRACT
Comparison of the levels of nucleotide diversity in humans and apes may provide valuable information for inferring the demographic history of these species, the effect of social structure on genetic diversity, patterns of past migration, and signatures of past selection events. Previous DNA sequence data from both the mitochondrial and the nuclear genomes suggested a much higher level of nucleotide diversity in the African apes than in humans. Noting that the nuclear DNA data from the apes were very limited, we previously conducted a DNA polymorphism study in humans and another in chimpanzees and bonobos, using 50 DNA segments randomly chosen from the noncoding, nonrepetitive parts of the human genome. The data revealed that the nucleotide diversity (pi) in bonobos (0.077%) is actually lower than that in humans (0.087%) and that pi in chimpanzees (0.134%) is only 50% higher than that in humans. In the present study we sequenced the same 50 segments in 15 western lowland gorillas and estimated pi to be 0.158%. This is the highest value among the African apes but is only about two times higher than that in humans. Interestingly, available mtDNA sequence data also suggest a twofold higher nucleotide diversity in gorillas than in humans, but suggest a threefold higher nucleotide diversity in chimpanzees than in humans. The higher mtDNA diversity in chimpanzees might be due to the unique pattern in the evolution of chimpanzee mtDNA. From the nuclear DNA pi values, we estimated that the long-term effective population sizes of humans, bonobos, chimpanzees, and gorillas are, respectively, 10,400, 12,300, 21,300, and 25,200.
Subject(s)
Genetic Variation , Gorilla gorilla/genetics , Animals , Base Sequence/genetics , Sequence Analysis, DNAABSTRACT
Comparison of the levels of nucleotide diversity in humans and apes may provide much insight into the mechanisms of maintenance of DNA polymorphism and the demographic history of these organisms. In the past, abundant mitochondrial DNA (mtDNA) polymorphism data indicated that nucleotide diversity (pi) is more than threefold higher in chimpanzees than in humans. Furthermore, it has recently been claimed, on the basis of limited data, that this is also true for nuclear DNA. In this study we sequenced 50 noncoding, nonrepetitive DNA segments randomly chosen from the nuclear genome in 9 bonobos and 17 chimpanzees. Surprisingly, the pi value for bonobos is only 0.078%, even somewhat lower than that (0.088%) for humans for the same 50 segments. The pi values are 0.092, 0.130, and 0.082% for East, Central, and West African chimpanzees, respectively, and 0.132% for all chimpanzees. These values are similar to or at most only 1.5 times higher than that for humans. The much larger difference in mtDNA diversity than in nuclear DNA diversity between humans and chimpanzees is puzzling. We speculate that it is due mainly to a reduction in effective population size (N(e)) in the human lineage after the human-chimpanzee divergence, because a reduction in N(e) has a stronger effect on mtDNA diversity than on nuclear DNA diversity. Sequence data from this article have been deposited with the GenBank Data libraries under accession nos. AY 275957-AY 277244.
Subject(s)
Base Sequence/genetics , Genetic Variation , Pan paniscus/genetics , Pan troglodytes/genetics , Animals , Cell Nucleus/genetics , DNA/genetics , DNA, Mitochondrial/genetics , Evolution, Molecular , Geography , Humans , Molecular Sequence Data , Polymorphism, Single Nucleotide , Sequence Analysis, DNA , Species SpecificityABSTRACT
Although much is known about genetic variation in human and African great ape (chimpanzee, bonobo, and gorilla) genomes, substantially less is known about variation in gene-expression profiles within and among these species. This information is necessary for defining transcriptional regulatory networks that contribute to complex phenotypes unique to humans or the African great apes. We took a systematic approach to this problem by investigating gene-expression profiles in well-defined cell populations from humans, bonobos, and gorillas. By comparing these profiles from 18 human and 21 African great ape primary fibroblast cell lines, we found that gene-expression patterns could predict the species, but not the age, of the fibroblast donor. Several differentially expressed genes among human and African great ape fibroblasts involved the extracellular matrix, metabolic pathways, signal transduction, stress responses, as well as inherited overgrowth and neurological disorders. These gene-expression patterns could represent molecular adaptations that influenced the development of species-specific traits in humans and the African great apes.