Search PubMed⌕ Search

Biomedical subjects

A J Pakstis

Publications and source records attributed to A J Pakstis.

71 records · Page 4Linked to original sources
PubMed1988

Evidence against linkage of schizophrenia to markers on chromosome 5 in a northern Swedish pedigree.

Schizophrenia is a severe mental illness with a typically chronic course affecting nearly 1% of the human population. It is generally accepted that genetic factors have an important pathogenic role in a substantial portion of schizophrenia cases; however, despite decades of family studies, there is no agreed-upon mode of inheritance. The discovery of genetic aetiologic factors and resolution of the inheritance pattern(s) will undoubtably emerge from genetic linkage studies. With these objectives in mind, we undertook a linkage project, starting in 1985, in a previously well-documented kindred from north Sweden. Multipoint linkage analyses were used to screen the proximal long arm of chromosome 5 using restriction fragment length polymorphism (RFLP) markers at five loci and the distal long arm using RFLPs at two loci, one of which was the locus for the glucocorticoid receptor. We found strong evidence against linkage between schizophrenia and the seven loci. These results, together with the positive evidence for linkage of schizophrenia with markers in the proximal long arm of chromosome 5 lead us to conclude that the genetic factors underlying schizophrenia are heterogeneous.

Chromosomes, Human, Pair 5↗
PubMed1988

Tyrosine hydroxylase maps to the short arm of chromosome 11 proximal to the insulin and HRAS1 loci.

Tyrosine hydroxylase (TH) is the rate-limiting enzyme for catecholamine biosynthesis and a candidate gene for manic-depressive illness. The TH locus was typed for a BglII RFLP using a cDNA clone Ty7 in four large kindreds. Pairwise analyses and multipoint analyses were carried out to map the TH locus more precisely in the region of the linked markers: D11S12, INS, and HRAS1 on 11p. Results confirm the close linkage between TH with these previously mapped markers and support a most likely ordering which places TH on the side of INS where the centromere lies.

Chromosome Mapping↗
PubMed1988

D10S20, a previously unmapped RFLP (OS-3), is located on 10q near D10S4.

The locus recognized by the probe OS-3 is assigned to chromosome 10 both by Southern blot analysis of a panel of somatic cell hybrid DNAs and by genetic linkage to markers already assigned to chromosome 10. In Caucasians this probe recognizes a three-allele TaqI RFLP as well as two-allele BanII and RsaI RFLPs which are both in strong linkage disequilibrium with each other and with the TaqI RFLP. The D10S20 locus defined by this probe maps 5.5 cM distal to D10S4 on the long arm of chromosome 10. Because this human clone hybridizes with mouse genomic DNA, it will be useful in comparative mapping studies.

Alleles↗
PubMed1986

Progress toward resolving the possible linkage of multiple endocrine neoplasia type 2A to haptoglobin and group-specific loci: use of restriction fragment length polymorphisms extends exclusion region.

In an earlier paper, positive but nonsignificant lod scores were found in pair-wise linkage tests between multiple endocrine neoplasia type 2A (MEN-2A) and both the haptoglobin (HP) locus on chromosome 16 and group-specific component (GC) locus on chromosome 4. Recently discovered restriction fragment length polymorphisms for HP and for metallothionein 2 processed pseudogene 1 (MT2P1) near GC have made it possible to carry out a more powerful set of linkage tests with MEN-2A. This paper reports the results of such linkage analyses employing both pair-wise and multipoint tests. Close linkage of HP on chromosome 16 and MEN-2A is excluded. Linkage of MEN-2A on chromosome 4 with GC is excluded on the MT2P1 side of GC in a 7-centimorgan interval around MT2P1.

Blood Protein Electrophoresis↗
PubMed1978

Gene frequency estimates for samples of Black and White twins from the Philadelphia metropolitan area.

Maximum likelihood estimates of gene frequencies and their standard errors are presented for 21 blood group and serum protein polymorphisms. The observed frequencies for certain high and low frequency antigens also are reported. The data come from a sample of 399 same-sex twin pairs and two sets of triplets from the Greater Philadelphia urban region encompassing roughly five counties in southeastern Pennsylvania and three counties of southern New Jersey. Analyses are carried out separately for the four subgroups created by subdividing the sample by race and co-twin. Total sample estimates are also calculated within the two socially defined racial groups. The gene frequency estimates generally appear to be consistent with previously reported data for U.S. urban populations. The frequency of the Fy allele in the Duffy system, however, seems to be the highest value thus far published for a white population. The white sample Fy allele very well may be a heterogeneous class in which only a very small fraction is comparable to the Fy allele common in the black sample.

Black People↗
PubMedDate not supplied

Understanding human DNA sequence variation.

Over the past century researchers have identified normal genetic variation and studied that variation in diverse human populations to determine the amounts and distributions of that variation. That information is being used to develop an understanding of the demographic histories of the different populations and the species as a whole, among other studies. With the advent of DNA-based markers in the last quarter century, these studies have accelerated. One of the challenges for the next century is to understand that variation. One component of that understanding will be population genetics. We present here examples of many of the ways these new data can be analyzed from a population perspective using results from our laboratory on multiple individual DNA-based polymorphisms, many clustered in haplotypes, studied in multiple populations representing all major geographic regions of the world. These data support an "out of Africa" hypothesis for human dispersal around the world and begin to refine the understanding of population structures and genetic relationships. We are also developing baseline information against which we can compare findings at different loci to aid in the identification of loci subject, now and in the past, to selection (directional or balancing). We do not yet have a comprehensive understanding of the extensive variation in the human genome, but some of that understanding is coming from population genetics.

Base Sequence↗