| 1. |
- Gilbert, M. Thomas P., et al.
(författare)
-
Intraspecific phylogenetic analysis of Siberian woolly mammoths using complete mitochondrial genomes
- 2008
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 105:24, s. 8327-8332
-
Tidskriftsartikel (refereegranskat)abstract
- We report five new complete mitochondrial DNA (mtDNA) genomes of Siberian woolly mammoth (Mammuthus primigenius), sequenced with up to 73-fold coverage from DNA extracted from hair shaft material. Three of the sequences present the first complete mtDNA genomes of mammoth clade II. Analysis of these and 13 recently published mtDNA genomes demonstrates the existence of two apparently sympatric mtDNA clades that exhibit high interclade divergence. The analytical power afforded by the analysis of the complete mtDNA genomes reveals a surprisingly ancient coalescence age of the two clades, approximate to 1-2 million years, depending on the calibration technique. Furthermore, statistical analysis of the temporal distribution of the C-14 ages of these and previously identified members of the two mammoth clades suggests that clade II went extinct before clade I. Modeling of protein structures failed to indicate any important functional difference between genomes belonging to the two clades, suggesting that the loss of clade II more likely is due to genetic drift than a selective sweep.
|
|
| 2. |
- Miller, Webb, et al.
(författare)
-
The mitochondrial genome sequence of the Tasmanian tiger (Thylacinus cynocephalus).
- 2009
-
Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1088-9051 .- 1549-5469. ; 19:2, s. 213-20
-
Tidskriftsartikel (refereegranskat)abstract
- We report the first two complete mitochondrial genome sequences of the thylacine (Thylacinus cynocephalus), or so-called Tasmanian tiger, extinct since 1936. The thylacine's phylogenetic position within australidelphian marsupials has long been debated, and here we provide strong support for the thylacine's basal position in Dasyuromorphia, aided by mitochondrial genome sequence that we generated from the extant numbat (Myrmecobius fasciatus). Surprisingly, both of our thylacine sequences differ by 11%-15% from putative thylacine mitochondrial genes in GenBank, with one of our samples originating from a direct offspring of the previously sequenced individual. Our data sample each mitochondrial nucleotide an average of 50 times, thereby providing the first high-fidelity reference sequence for thylacine population genetics. Our two sequences differ in only five nucleotides out of 15,452, hinting at a very low genetic diversity shortly before extinction. Despite the samples' heavy contamination with bacterial and human DNA and their temperate storage history, we estimate that as much as one-third of the total DNA in each sample is from the thylacine. The microbial content of the two thylacine samples was subjected to metagenomic analysis, and showed striking differences between a wild-captured individual and a born-in-captivity one. This study therefore adds to the growing evidence that extensive sequencing of museum collections is both feasible and desirable, and can yield complete genomes.
|
|
| 3. |
- Miller, Webb, et al.
(författare)
-
Sequencing the nuclear genome of the extinct woolly mammoth.
- 2008
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 456:7220, s. 387-390
-
Tidskriftsartikel (refereegranskat)abstract
- In 1994, two independent groups extracted DNA from several Pleistocene epoch mammoths and noted differences among individual specimens. Subsequently, DNA sequences have been published for a number of extinct species. However, such ancient DNA is often fragmented and damaged, and studies to date have typically focused on short mitochondrial sequences, never yielding more than a fraction of a per cent of any nuclear genome. Here we describe 4.17 billion bases (Gb) of sequence from several mammoth specimens, 3.3 billion (80%) of which are from the woolly mammoth (Mammuthus primigenius) genome and thus comprise an extensive set of genome-wide sequence from an extinct species. Our data support earlier reports that elephantid genomes exceed 4 Gb. The estimated divergence rate between mammoth and African elephant is half of that between human and chimpanzee. The observed number of nucleotide differences between two particular mammoths was approximately one-eighth of that between one of them and the African elephant, corresponding to a separation between the mammoths of 1.5-2.0 Myr. The estimated probability that orthologous elephant and mammoth amino acids differ is 0.002, corresponding to about one residue per protein. Differences were discovered between mammoth and African elephant in amino-acid positions that are otherwise invariant over several billion years of combined mammalian evolution. This study shows that nuclear genome sequencing of extinct species can reveal population differences not evident from the fossil record, and perhaps even discover genetic factors that affect extinction.
|
|
| 4. |
- Miller, Webb, et al.
(författare)
-
28-Way vertebrate alignment and conservation track in the UCSC Genome Browser
- 2007
-
Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1088-9051 .- 1549-5469. ; 17:12, s. 1797-1808
-
Tidskriftsartikel (refereegranskat)abstract
- This article describes a set of alignments of 28 vertebrate genome sequences that is provided by the UCSC Genome Browser. The alignments can be viewed on the Human Genome Browser (March 2006 assembly) at http://genome.ucsc.edu, downloaded in bulk by anonymous FTP from http://hgdownload.cse.ucsc.edu/goldenPath/hg18/multiz28way, or analyzed with the Galaxy server at http://g2.bx.psu.edu. This article illustrates the power of this resource for exploring vertebrate and mammalian evolution, using three examples. First, we present several vignettes involving insertions and deletions within protein-coding regions, including a look at some human-specific indels. Then we study the extent to which start codons and stop codons in the human sequence are conserved in other species, showing that start codons are in general more poorly conserved than stop codons. Finally, an investigation of the phylogenetic depth of conservation for several classes of functional elements in the human genome reveals striking differences in the rates and modes of decay in alignability. Each functional class has a distinctive period of stringent constraint, followed by decays that allow (for the case of regulatory regions) or reject (for coding regions and ultraconserved elements) insertions and deletions.
|
|
