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D W Cooper

Publications and source records attributed to D W Cooper.

At least 19 recordsLinked to original sources
PubMed1992

Evolution of sex determination and the Y chromosome: SRY-related sequences in marsupials.

In mammals, testis determination is under the control of the testis-determining factor borne by the Y chromosome. SRY, a gene cloned from the sex-determining region of the human Y chromosome, has been equated with the testis-determining factor in man and mouse. We have used a human SRY probe to identify and clone related genes from the Y chromosome of two marsupial species. Comparisons of eutherian and metatherian Y-located SRY sequences suggest rapid evolution of these genes, especially outside the region encoding the DNA-binding HMG box. The SRY homologues, together with the mouse Ube1y homologues, are the first genes to be identified on the marsupial Y chromosome.

Amino Acid Sequence↗
PubMed1992

PCR derived cDNA clones for X-linked phosphoglycerate kinase-1 in a marsupial, the tammar wallaby (Macropus eugenii).

cDNA clones for the X-linked PGK-1 were obtained from a tammar wallaby liver by PCR and sequenced. The PGK-1 gene published here is the consensus sequence of those clones. The sequence represents an open reading frame of 1251 bp. Sequence comparisons to X-linked and autosomal sequences showed the greatest homology with the X-linked PGK-1 genes in eutherian species. This sequence opens the way for studying the paternal X inactivation phenomenon in marsupials and will assist in defining the time course of mammalian evolution.

Amino Acid Sequence↗
PubMed1992

Progression of HIV-related disease is associated with HLA DQ and DR alleles defined by restriction fragment length polymorphisms.

A cohort of 139 hemophiliacs was typed for HLA D region genes by means of restriction fragment length polymorphisms (RFLPs) detected by HLA DQ and DR gene probes. Disease progression was studied in the 65 HIV antibody-positive patients, who were infected by contaminated clotting factor before 1985. Strong associations were found between disease progression in HIV-infected patients and allelic DNA fragments revealed by a DQ alpha cDNA probe. A 5.5 kb fragment was reduced in frequency and a 4.6 kb fragment increased in frequency (p less than 0.005) in the faster progressing group, as measured both by development of CDC Category IV clinical symptoms and CD4 number less than 200 x 10(6)/l. These results correlate with DR types deduced from the RFLP patterns revealed by DR beta and DQ alpha gene probes. A decrease in DR4 and an increase in both DR5 and the DR3 subtype found in the A1 B8 DR3 haplotype were associated with disease progression (p less than 0.05).

Alleles↗
PubMed1990

Absence of close linkage between maternal genes for susceptibility to pre-eclampsia/eclampsia and HLA DR beta.

To test the possibility that maternally expressed susceptibility genes for pre-eclampsia/eclampsia are closely linked to the HLA region on chromosome 6 of the human genome, members of ten pedigrees with multiple cases of these disorders were typed for HLA DR beta restriction fragment length polymorphisms by means of TaqI digests. The data were analysed by the LIPED program to calculate lod scores, by several programs to detect potential heterogeneity of recombination fraction between pedigrees, and by the affected-sibling and the affected-pedigree-member methods. The results exclude close linkage. If the putative susceptibility genes lie on chromosome 6 they must lie at least 5 centiMorgans, and probably more, from the HLA DR beta loci. No indication of linkage at higher recombination fractions was found. The main maternally expressed genes affecting susceptibility to pre-eclampsia are not in the HLA region.

Adult↗
PubMed1990

Immunoglobulin G levels in fetal and newborn tammar wallabies (Macropus eugenii).

Immunoglobulin G (IgG) was measured in fetal, neonatal and colostral samples from the tammar wallaby (Macropus eugenii) in order to study the possibility of passively acquired immunity. Samples were obtained from young at a known stage of gestation and at known times (to the minute) after birth. IgG was present (in increasing levels of concentration) in fetal serum, neonatal serum and colostrum. Since the fetus and neonate are probably unable to make immunoglobulin (Ig), it is hypothesized that transplacental and trans-gut transmission takes place from mother to offspring. The vascular yolk sac placenta has a high concentration of IgG, and is the most likely route of transmission from mother to young. Some observations were made of IgA which was found only in colostrum. No Ig of either kind was found in yolk sac fluid.

Animals↗
PubMed1989

Linkage studies of HLA and insulin gene restriction fragment length polymorphisms in families with IDDM.

Linkage analysis of HLA DR antigen as well as DR and DQ restriction fragment length polymorphism (RFLP) data using the LIPED computer program and various three-allele disease locus models showed very close linkage to an insulin-dependent diabetes mellitus (IDDM)-susceptibility locus. RFLP data alone were equal or superior to conventional HLA antigen typing in the linkage analysis. Insulin gene restriction fragment data were analyzed for evidence of either a susceptibility locus linked to the insulin gene or an effect of alleles at the insulin locus on the HLA-linked susceptibility gene. No evidence was found of any effect of the insulin gene, and it is suggested that alternative explanations of the reported population associations between the insulin gene and IDDM should be considered.

Computer Simulation↗
PubMed1989

No association between the ovine leucocyte antigen (OLA) system in the Australian merino and susceptibility to Haemonchus contortus infection.

A genetic analysis has been made of the Ovine Leucocyte Antigenic (OLA) system in Australian merinos. The animals consisted of sires, dams and their progeny. The typing data were consistent with previous findings of a high degree of polymorphism. At least two closely linked loci with several alleles at each are necessary to explain the data. No evidence was found for an association between OLA types and three measures of susceptibility to infection by the blood-sucking parasite Haemonchus contortus. Attention is drawn to the utility of half-sib data for analysis of the genetic control of resistance to parasites in sheep and other animals with a similar breeding structure.

Animals↗
PubMed1989

A marsupial phosphoglycerate kinase (PGK) processed pseudogene.

A clone that cross-hybridized with a full-length human cDNA PGK probe was isolated from a hill kangaroo (Macropus robustus: Marsupialia) lambda EMBL4 EcoRI genomic library. The clone was sequenced and demonstrated to be a pseudogene, with two deletions (one of 3 bases, the other 24 bases long), one single base insertion, and a nonsense mutation with respect to the functional human X-linked gene. It is flanked by terminal repeats in the 5' and 3' noncoding regions, but it has no 3' poly(A) remnant. The 3' untranslated region has a 34-bp sequence, with 29 bp homologous to the human 3' untranslated region. The overall percentage homology with the mouse and human X-linked PGK indicates that this pseudogene is probably more closely related to eutherian X-linked PGK genes than to the autosomal form. The results also suggest that pseudogenes are of considerable antiquity (greater than 100 MYr) in the mammalian lineage.

Animals↗
PubMed1988

Lack of evidence for complement-dependent cytotoxic antibodies to fetal paternally derived antigens in the marsupial Macropus eugenii (tammar wallaby).

A total of 241 serum samples from 145 parous tammar wallabies (Macropus eugenii) were screened for presence of antibodies to paternally derived antigens of the fetus. These samples were taken at different stages in late pregnancy after placental contact was intimate and after birth. Complement-dependent cytotoxicity tests were unable to detect any specific antibodies. It is concluded that the yolk sac placenta of M. eugenii does not allow intimate enough contact between fetal tissues and the maternal circulation to induce formation of cytotoxic antibodies by its mother. This is in contrast to eutherian mammals, in which such production of cytotoxic antibodies occurs frequently as a result of pregnancy. Together with other data it is suggested that the short implantation period in M. eugenii, which is common to all marsupials, has probably not evolved to prevent maternal immune attack upon the conceptus.

Animals↗
PubMed1979

Expression of PGK-A in the Australian brush-tailed possum, Trichosurus vulpecula (Kerr), consistent with paternal X inactivation.

An extensive survey of erythrocytes of marsupials other than kangaroos for electrophoretic variation if X-linked enzymes revealed two rare PGK-A phenotypes in the phalangerid Trichosurus vupecula and one in Trichosurus caninus. Four putatively heterozygous females expressed only the variant allelic isozyme in some tissues but expressed a trace of the normal isozyme in others. A putatively hemizygous male expressed only the variant isozyme in all tissues. The phenotypic patterns were consistent with those observed in kangaroos known to exhibit partial or complete parternal X inactivation in cells of females. Tow of the T. vulpecula were a mother and her female pouch young, further suggesting that paternal X inactivation occurs in T. vulpecula. This peculiar mechanism of dosage compensation may not be restricted to kangaroos.

Animals↗
PubMed1979

Marsupial--mouse cell hybrids containing fragments of the marsupial X chromosome.

Hybrids were obtained from fusions of HPRT-deficient mouse fibroblasts and marsupial lymphocytes. These hybrids retained no identifiable marsupial chromosomes, but all expressed the marsupial form of HPRT. Half the clones also expressed marsupial PGK-A, and half of these also marsupial G6PD; no other marsupial allozyme markers were detected. Since G6PD is known to be sex linked in these species, we conclude that Hpt and Pgk-A are also located on the X chromosome and the markers lie in the order Hpt-Pgk-A-Gpd.

Animals↗