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A Gullberg

Publications and source records attributed to A Gullberg.

At least 19 recordsLinked to original sources
PubMed2000

The mitochondrial genome of the sperm whale and a new molecular reference for estimating eutherian divergence dates.

Extant cetaceans are systematically divided into two suborders: Mysticeti (baleen whales) and Odontoceti (toothed whales). In this study, we have sequenced the complete mitochondrial (mt) genome of an odontocete, the sperm whale (Physeter macrocephalus), and included it in phylogenetic analyses together with the previously sequenced complete mtDNAs of two mysticetes (the fin and blue whales) and a number of other mammals, including five artiodactyls (the hippopotamus, cow, sheep, alpaca, and pig). The most strongly supported cetartiodactyl relationship was: outgroup,((pig, alpaca), ((cow, sheep),(hippopotamus,(sperm whale,(baleen whales))))). As in previous analyses of complete mtDNAs, the sister-group relationship between the hippopotamus and the whales received strong support, making both Artiodactyla and Suiformes (pigs, peccaries, and hippopotamuses) paraphyletic. In addition, the analyses identified a sister-group relationship between Suina (the pig) and Tylopoda (the alpaca), although this relationship was not strongly supported. The paleontological records of both mysticetes and odontocetes extend into the Oligocene, suggesting that the mysticete and odontocete lineages diverged 32-34 million years before present (MYBP). Use of this divergence date and the complete mtDNAs of the sperm whale and the two baleen whales allowed the establishment of a new molecular reference, O/M-33, for dating other eutherian divergences. There was a general consistency between O/M-33 and the two previously established eutherian references, A/C-60 and E/R-50. Cetacean (whale) origin, i.e., the divergence between the hippopotamus and the cetaceans, was dated to approximately 55 MYBP, while basal artiodactyl divergences were dated to >/=65 MYBP. Molecular estimates of Tertiary eutherian divergences were consistent with the fossil record.

Animals↗
PubMed2000

The phylogenetic position of the Talpidae within eutheria based on analysis of complete mitochondrial sequences.

The complete mitochondrial (mt) genome of the mole Talpa europaea was sequenced and included in phylogenetic analyses together with another lipotyphlan (insectivore) species, the hedgehog Erinaceus europaeus, and 22 other eutherian species plus three outgroup taxa (two marsupials and a monotreme). The phylogenetic analyses reconstructed a sister group relationship between the mole and fruit bat Artibeus jamaicensis (order Chiroptera). The Talpa/Artibeus clade constitutes a sister clade of the cetferungulates, a clade including Cetacea, Artiodactyla, Perissodactyla, and Carnivora. A monophyletic relationship between the hedgehog and the mole was significantly rejected by maximum parsimony and maximum likelihood. Consistent with current systematic schemes, analyses of complete cytochrome b genes including the shrew Sorex araneus (family Soricidae) revealed a close relationship between Talpidae and Soricidae. The analyses of complete mtDNAs, along with the findings of other insectivore studies, challenge the maintenance of the order Lipotyphla as a taxonomic unit and support the elevation of the Soricomorpha (with the families Talpidae and Soricidae and possibly also the Solenodontidae and Tenrecidae) to the level of an order, as previously proposed in some morphological studies.

Animals↗
PubMed2000

Molecular estimates of primate divergences and new hypotheses for primate dispersal and the origin of modern humans.

The concept of recent hominoid divergences has been a mainstay in molecular primatology since the 1970's. However, the ages allocated to the calibration points used to establish these divergence times and the estimates resulting from their application, notably the commonly accepted divergence between Pan (chimpanzees) and Homo 5 million years before present (MYBP), are now palaeontologically refutable. Here we estimate the ages of various primate divergences using three references with a more detailed fossil record than any of the traditional primate calibration points. Our findings suggest that the latter yield datings that are too recent by a factor of about two. For example, our estimates place the divergence between Pan and Homo 10.5-13 MYBP. The revised estimates of primate divergence times suggest a new hypothesis for primate evolution and dispersal: that the divergence between strepsirhines (lorises, lemurs) and anthropoids was contemporary with the break-up of Southern continents about 90 MYBP, with strepsirhines becoming isolated on Madagascar and later dispersing to Africa (and Asia) and anthropoids evolving in South America and subsequently colonizing Africa (and Asia), or possibly North America. In addition we present a new hypothesis, which accommodates the strikingly similar coalescence times for human mitochondrial DNA and the Y-chromosome. This hypothesis posits a common mitochondrial and Y-chromosome bottleneck about 400,000 years ago, associated with the origination of the human 2n = 46 karyotype, obstructing genetic exchange with the 2n = 48 Homo contemporaries.

Africa↗
PubMed1999

The mitochondrial DNA molecule of the aardvark, Orycteropus afer, and the position of the Tubulidentata in the eutherian tree.

An outstanding problem in mammal phylogeny is the relationship of the aardvark (Orycteropus afer), the only living species of the order Tubulidentata, to the extant eutherian lineages. In order to examine this problem the complete mitochondrial DNA (mtDNA) molecule of the aardvark was sequenced and analysed. The aardvark tRNA-Ser (UCN) differs from that of other mammalian mtDNAs reported and appears to have reversed to the ancestral secondary structure of non-mammalian vertebrates and mitochondrial tRNAs in general. Phylogenetic analysis of 12 concatenated protein-coding genes (3325 amino acids) included the aardvark and 15 additional eutherians, two marsupials and a monotreme. The most strongly supported tree identified the aardvark as a sister group of a clade including the armadillo (Xenarthra) and the Cetferungulata (carnivores, perissodactyls, artiodactyls and cetaceans). By applying three molecular calibration points the divergence between the aardvark and armadillo-cetferungulates was estimated at ca. 90 million years before present.

Animals↗
PubMed1999

Mortality statistics in immigrant research: method for adjusting underestimation of mortality.

BACKGROUND: It is difficult to carry out fair comparisons of the mortality of different ethnic groups in a population in register-based studies because sizeable numbers of immigrants who subsequently leave their new homeland fail to register this fact with the national registration authorities. In this article we present a method which attempts to address these problems. METHODS: Age-standardized mortality rates for native Swedes and immigrants in the age group 20-64 years were calculated for all individuals who either were included in the Swedish Population Censuses for 1985 or 1990, or who moved to Sweden during the period November 1990-1994. In order to define the population under scrutiny different sources of income are used as indicators of residence in the country. RESULTS: When an analysis is made of all nationally registered individuals, significantly reduced death rates are found among immigrants outside the north-east of Europe compared to those for Swedish-born people. Extremely low death rates are found for those born in Turkey, Southern Europe, Latin America, Asia, and Africa and for those who are younger and without any income. When the income criterion is introduced, there is a change so that the earlier significantly reduced relative death risks for immigrants born outside the north-east of Europe for some subgroups are no longer significantly lowered. CONCLUSION: This study has important implications for the interpretation of every study of mortality among immigrants based on official mortality statistics. Using information about income as an indicator of residence in the country appears to be a method which can be pursued further in order to achieve a more accurate understanding of mortality among immigrant groups.

Adult↗
PubMed1998

The complete mitochondrial DNA sequence of the rabbit, Oryctolagus cuniculus.

The nucleotide sequence of the complete mitochondrial DNA (mtDNA) molecule of the rabbit (Oryctolagus cuniculus, order Lagomorpha) was determined. The length of the molecule is 17,245 nt, but the length is not absolute due to the presence of different numbers of repeated motifs in the control region. The organization and gene contents of the mtDNA of the rabbit conform to those of other eutherian species. The putative secondary structures of the tRNAs of the rabbit have been described. These structures as well as the structure of the L-strand origin of replication comply with those characteristic for eutherians in general. The compositional differences between the two mtDNA strands have also been detailed.

Animals↗
PubMed1998

Molecular timing of primate divergences as estimated by two nonprimate calibration points.

The complete mitochondrial DNA (mtDNA) molecule of the hamadryas baboon, Papio hamadryas, was sequenced and included in a molecular analysis of 24 complete mammalian mtDNAs. The particular aim of the study was to time the divergence between Cercopithecoidea and Hominoidea. That divergence, set at 30 million years before present (MYBP) was a fundamental reference for the original proposal of recent hominoid divergences, according to which the split among gorilla, chimpanzee, and Homo took place 5 MYBP. In the present study the validity of the postulated 30 MYBP dating of the Cercopithecoidea/Hominoidea divergence was examined by applying two independent nonprimate molecular references, the divergence between artiodactyls and cetaceans set at 60 MYBP and that between Equidae and Rhinocerotidae set at 50 MYBP. After calibration for differences in evolutionary rates, application of the two references suggested that the Cercopithecoidea/Hominoidea divergence took place >50 MYBP. Consistent with the marked shift in the dating of the Cercopithecoidea/Hominoidea split, all hominoid divergences receive a much earlier dating. Thus the estimated date of the divergence between Pan (chimpanzee) and Homo is 10-13 MYBP and that between Gorilla and the Pan/Homo linage approximately 17 MYBP. The same datings were obtained in an analysis of clocklike evolving genes. The findings show that recalculation is necessary of all molecular datings based directly or indirectly on a Cercopithecoidea/Hominoidea split 30 MYBP.

Animals↗
PubMed1998

Avoidable mortality among psychiatric patients.

Avoidable mortality is a selection of causes of death considered to be amenable to health care and thereby used as an indicator of the quality of health care. In this study avoidable mortality for more than 30,000 psychiatric patients discharged from any hospital of Stockholm County between 1981 and 1985 has been followed up in the Cause of Death Register for the period 1986-1990. Standardised rate ratios were calculated for different groups of psychiatric disorders compared to the general population of Stockholm County for indicators of avoidable mortality, suicide, other mortality ("unavoidable") and causes possibly related to treatment with psychotrophic drugs. As expected, the psychiatric patients had the most pronounced elevated risk for suicide. i.e. 6- to 24-fold compared to the general population, and noticeably more elevated for women. It is also noteworthy that the relative mortality risks for diagnoses amenable to medical interventions and potential side-effects of psychotrophic drugs are higher than for other causes of death ("unavoidable"). The relative risks for avoidable mortality were 4.7 for men and 3.8 for women and for diagnoses possibly related to side-effects of psychotrophic drugs, 7.2. The relative risks for "unavoidable" mortality were 3.4 for men and 3.2 for women. The excess avoidable mortality rates for psychiatric patients and the elevated suicide risk, especially for female patients, are warning signals of shortcomings in psychiatric care that warrants further investigation.

Adult↗
PubMed1997

Microsatellites in the sand lizard (Lacerta agilis): description, variation, inheritance, and applicability.

We developed microsatellite markers for the sand lizard (Lacerta agilis) to enable investigations of the genetic variability within and among populations with a heterogeneous spatial distribution in Sweden. The populations, which could not be characterized by variation in allozymes or mitochondrial DNA, had a substantial level of variability in microsatellite loci. However, the variability in Swedish populations was limited compared to a large, outbred Hungarian population. In the sand lizard, the number of (GT/CA)n repeats was approximately three times higher than that for (CT/GA)n. The number of repeats and the frequency of microsatellites were within the range reported for other species. Three of nine microsatellite loci showed alleles that could not be amplified, which is in agreement with recent reports describing microsatellite "null alleles" as a common occurrence. We discuss the caution which this calls for when calculating paternity probabilities and when estimating between-population allelic differentiation. A potential problem with different mutation rates for alleles within the same locus is discussed.

Alleles↗
PubMed1997

Phylogenetic analyses of mitochondrial DNA suggest a sister group relationship between Xenarthra (Edentata) and Ferungulates.

Phylogenetic analysis of 12 protein-coding genes from complete mitochondrial DNA (mtDNA) molecules of various mammals including a xenarthran representative, the armadillo (Dasypus novemcinctus), showed that the order Xenarthra (Edentata) is a sister group to the ferungulates (carnivores, perissodactyls, artiodactyls, cetaceans). Morphological and previous molecular analyses have placed the Xenarthra basal to other extant eutherians. The present findings are in striking contrast with that understanding. The results suggest that Xenarthra and ferungulates separated about 86 MYA.

Amino Acid Sequence↗
PubMed1996

Comparison between the complete mitochondrial DNA sequences of Homo and the common chimpanzee based on nonchimeric sequences.

The complete mitochondrial DNA (mtDNA) molecules of Homo and of the common chimpanzee were sequenced. Each sequence was established from tissue of one individual and thus nonchimeric. Both sequences were assembled in their entirety from natural (not PCR amplified) clones. Comparison with sequences in the literature identified the chimpanzee specimen as Pan troglodytes verus, the West African variety of the species. The nucleotide difference between the complete human and chimpanzee sequences is 8.9%. The difference between the control regions of the two sequences is 13.9% and that between the remaining portions of the sequences 8.5%. The mean amino acid difference between the inferred products of the 13 peptide-coding genes is 4.4%. Sequences of the complete control regions, the complete 12S rRNA genes, the complete cytochrome b genes, and portions of the NADH4 and NADH5 genes of two other chimpanzee specimens showed that they were similar but strikingly different from the same regions of the completely sequenced molecule from Pan troglodytes verus. The two specimens were identified as Pan troglodytes troglodytes, the Central African variety of the common chimpanzee.

Animals↗
PubMed1996

Pattern and timing of evolutionary divergences among hominoids based on analyses of complete mtDNAs.

We have examined and dated primate divergences by applying a newly established molecular/ paleontological reference, the evolutionary separation between artiodactyls and cetaceans anchored at 60 million years before present (MYBP). Owing to the morphological transformations coinciding with the transition from terrestrial to aquatic (marine) life and the large body size of the animals (which makes their fossils easier to find), this reference can be defined, paleontologically, within much narrower time limits compared to any local primate calibration marker hitherto applied for dating hominoid divergences. Application of the artiodactyl/ cetacean reference (A/C-60) suggests that hominoid divergences took place much earlier than has been concluded previously. According to a homogeneous-rate model of sequence evolution, the primary hominoid divergence, i.e., that between the families Hylobatidae (gibbons) and Hominidae, was dated at approximately 36 MYBP. The corresponding dating for the divergence between Pongo (orangutan) and Gorilla-Pan (chimpanzee) -Homo is approximately 24.5 MYBP, that for Gorilla vs Homo-Pan is approximately 18 MYBP, and that for Homo vs Pan approximately 13.5 MYBP. The split between Sumatran and Bornean orangutans was dated at approximately 10.5 MYBP and that between the common and pygmy chimpanzees at approximately 7 MYBP. Analyses of a single gene (cytochrome b) suggest that the divergence within the Catarrhini, i.e., between Hominoidea and Old World monkeys (Cercopithecoidea), took place > 40 MYBP; that within the Anthropoidea, i.e., between Catarrhini and Platyrrhini (New World monkeys), > 60 MYBP; and that between Anthropoidea and Prosimii (lemur), approximately 80 MYBP. These separation times are about two times more ancient than those applied previously as references for the dating of hominoid divergences. The present findings automatically imply a much slower evolution in hominoid DNA (both mitochondrial and nuclear) than commonly recognized.

Animals↗
PubMed1996

The complete mitochondrial DNA (mtDNA) of the donkey and mtDNA comparisons among four closely related mammalian species-pairs.

The nucleotide sequence of the complete mitochondrial genome of the donkey, Equus asinus, was determined. The length of the molecule is 16,670 bp. The length, however, is not absolute due to pronounced heteroplasmy caused by variable numbers of two types of repetitive motifs in the control region. The sequence of the repeats is (a) 5'-CACACCCA and (b) 5'-TGCGCGCA, respectively. The order of (a) and (b) can be expressed as {n[2(a)+(b)]+m(a)}. In 32 different clones analyzed the number of n and m ranged from 0 to 9 and 1 to 7. The two rRNA genes, the 13 peptide-coding genes, and the 22 tRNA genes of the donkey and the horse, Equus caballus, were compared in detail. Total nucleotide difference outside the control region was 6.9%. Nucleotide difference between peptide-coding genes ranged from 6.4% to 9.4% with a mean of 8.0%. In the inferred protein sequences of the 13 peptide-coding genes the amino acid difference was 0.2-8.8%, and the mean for the 13 concatenated amino acid sequences was 1.9%. In the 22 tRNA genes, the mean difference was 3.5%, and that in the two rRNA genes was 4.1%. The mtDNA differences between the donkey and the horse suggest that the evolutionary separation of the two species occurred approximately 9 million years ago. Analyses of differences among the mtDNAs of three other species-pairs, harbor seal/grey seal, fin whale/blue whale, and Homo/common chimpanzee, showed that the relative evolutionary rate of individual peptide-coding genes varies among different species-pairs and modes of comparison. The findings show that the superimposition of sequence data of one lineage for resolving and dating evolutionary divergences of other lineages should be performed with caution unless based on comprehensive data.

Animals↗
PubMed1996

The "Phoca standard": an external molecular reference for calibrating recent evolutionary divergences.

Comparison of the complete mitochondrial DNA (mtDNA) of the high-Arctic ringed seal (Phoca hispida) and the sub-Arctic harbour (P. vitulina) and grey (Halichoerus grypus) seals shows that they are genetically equidistant from one another. We relate the evolutionary divergence of the three species to expanding glaciation in the Arctic Basin and establish, in conjunction with mtDNA data, a standard reference for calibration of recent divergence events among mammalian taxa. In the present study, we apply the "Phoca standard" to the dating of divergences within the hominid phylogenetic tree. After determining the relative rates of substitution over all mitochondrial protein-coding genes in the different evolutionary lineages, we estimate that humans and chimpanzees diverged from each other 6.1 Mya (95% confidence limits: 5.2-6.9 Mya). The corresponding lower-limit divergence between common chimpanzee, Pan troglodytes, and pygmy chimpanzee, P. paniscus, occurred 3 (2.4-3.6) Mya, and the primary split within the P. troglodytes complex 1.6 (1.3-2.0) Mya. The analyses suggest that the split between Gorilla and Pan/Homo occurred 8.4 (7.3-9.4) Mya. They also suggest that Pongo (orangutan) and the lineage leading to gorillas, chimpanzees, and humans diverged 18.1 (16.5-19.6) Mya. The present analysis is independent of the hominid paleontological record and inferential morphological interpretations and thus is a novel approach to the lower-limit dating of recent divergences.

Animals↗
PubMed1996

Socioeconomic differences in 'avoidable' mortality in Sweden 1986-1990.

BACKGROUND: 'Avoidable' mortality is commonly studied as an indicator of the outcome of health care. In this study socioeconomic differences in avoidable mortality in Sweden from 1986 to 1990 are analysed and related methodological issues discussed. METHODS: The 1985 Swedish Population and Housing Census was linked to the National Cause of Death Register 1986-1990. Mortality from potentially 'avoidable' causes of death was analysed for the age group 21-64 years. Analyses were performed for different socioeconomic groups, blue-collar workers, white-collar workers and the self-employed as well as for individuals outside the labour market. Standardized Mortality Ratios were calculated using standardization by age and sex. RESULTS: For all indicators studied, the death rates for those not in work were higher than for people at work. The largest differences were found for chronic bronchitis, diabetes, bacterial meningitis, ulcer of the stomach and duodenum, chronic rheumatic heart disease, asthma and hypertensive and cerebrovascular disease. For these causes of death the risk of dying was between 3.1 and 7.5 times greater in the non-working population than in the work-force. The differences in avoidable mortality between blue-collar workers and white-collar workers and the self-employed were, however, much smaller. For most of the indicators no significant differences were found. For ulcers of the stomach and duodenum, however the death rate for blue-collar workers was 2.8 times higher than those for other categories in work. CONCLUSIONS: The small difference in mortality outcome for different socioeconomic groups within the work-force indicates an equal quality of care for these groups. The greatly increased risk among the non-working population, however, is a warning sign. These results may be due to a 'healthy worker' effect. The measurement of socioeconomic differences in mortality may be dependent on the time-period chosen between occupational exposure and mortality outcome.

Adult↗
PubMed1996

Cytochrome b nucleotide sequences and the identification of five primary lineages of extant cetaceans.

Relationships among and within baleen and toothed whales were examined using the complete sequence of the mitochondrial cytochrome b gene. Based on parsimony analyses of conservative nucleotide substitutions, five primary evolutionary lineages of extant cetaceans were identified, one represented by baleen whales (Mysticeti) and four represented by odontocetes (toothed whales). Based on the most comprehensive representation of taxa, both cetaceans and artiodactyls, the most parsimonious relationship among the five lineages is (Mysticeti, Odontoceti (Platanistoidea (Physeteroidea (Ziphioidea (Delphinida))))). This relationship, however, is labile and sensitive to ingroup representation and the choice of outgroup. The short nodes among the five cetacean lineages suggest that the divergence among these lineages occurred over a narrow time period, a finding consistent with the limited fossil evidence that indicates a major cetacean radiation 30-34 Mya. The level of divergence among the five cetacean lineages, and that seen between cetaceans and artiodactyls, suggests that cetaceans and artiodactyls had a common ancestor approximately 60 Mya.

Animals↗
PubMed1995

A molecular view of pinniped relationships with particular emphasis on the true seals.

Phylogenetic analysis of conservative nucleotide substitutions in 18 complete sequences of the mitochondrial cytochrome b gene of Phocidae (true seals), Odobenidae (walruses), and Otariidae (sea lions and fur seals), plus three ursid and three felid sequences, identified the pinnipeds as monophyletic with Otariidae and Odobenidae on a common evolutionary branch. Analysis of total nucleotide differences separated the evolutionary lineages of northern and southern phocids. Both lineages are distinct from the most ancestral phocid genus, Monachus (monk seals), represented by the Hawaiian monk seal. The inclusion of the Hawaiian monk seal in the subfamily Monachinae makes the subfamily paraphyletic. Among the northern phocids, the hooded seal (genus Cystophora, chromosome number 2n = 34) is sister taxon to the Phoca complex. The Phoca complex, which is characterized by the chromosome number 2n = 32, includes genus Phoca and the monotypic genus Halichoerus (grey seal). The comparison does not support a generic distinction of Halichoerus within the Phoca complex. The present data suggest that Cystophora and Phoca separated > or = 6 million years ago. Among the southern phocids the close molecular relationship of the Weddell and leopard seals relative to their morphological distinction exemplifies rapid adaptation to different ecological niches. This result stands in contrast to the limited morphological differentiation relative to the pronounced molecular distinctions that may occur within the Phoca complex.

Animals↗