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J Melnyk

Publications and source records attributed to J Melnyk.

At least 19 recordsLinked to original sources
PubMed2001

Identification of non-functional human VNO receptor genes provides evidence for vestigiality of the human VNO.

In mammals, the vomeronasal organ (VNO) contains chemosensory receptor cells that bind to pheromones and induce a variety of social and reproductive behaviors. It has been traditionally assumed that the human VNO (Jacobson's organ) is a vestigial structure, although recent studies have shown minor evidence for a structurally intact and possibly functional VNO. The presence and function of the human VNO remains controversial, however, as pheromones and VNO receptors have not been well characterized. In this study we screened a human Bacterial Artificial Chromosome (BAC) library with multiple primer sets designed from human cDNA sequences homologous to mouse VNO receptor genes. Utilizing these BAC sequences in addition to mouse VNO receptor sequences, we screened the High Throughput Genome Sequence (HTGS) database to find additional human putative VNO receptor genes. We report the identification of 56 BACs carrying 34 distinct putative VNO receptor gene sequences, all of which appear to be pseudogenes. Sequence analysis indicates substantial homology to mouse V1R and V2R VNO receptor families. Furthermore, chromosomal localization via FISH analysis and RH mapping reveal that the majority of the BACs are localized to telomeric and centromeric chromosomal localizations and may have arisen through duplication events. These data yield insight into the present state of pheromonal olfaction in humans and into the evolutionary history of human VNO receptors.

Amino Acid Sequence↗
PubMed1999

Contig assembly of bacterial artificial chromosome clones through multiplexed fluorescence-labeled fingerprinting.

A rapid multiplexed fingerprinting method has been developed for bacterial artificial chromosome (BAC) contig assembly. Defined subsets of BAC DNA fragments that result from digestion by three paired restriction endonucleases are labeled with unique fluorescent F-ddATP for each subset. Lists of the labeled fragment size are generated by an ABI 377 DNA sequencer and the GeneScan analysis software and then processed by an assembly program, FPC (Fingerprinted Contigs), to produce contig maps. Data obtained from the multiplexed labeling permit detection of smaller overlaps than is observed when data from a single double-digest are analyzed. The method has been tested on 98 BACs from chromosome 22 regions where large-scale sequencing is under way and also through simulation, using randomly generated BAC clones derived from existing DNA sequence data. In each case, contig assembly results demonstrated the advantages of multiplexed fingerprinting.

Chromosomes, Bacterial↗
PubMed1976

Karyotype analysis by computer and its application to mutagenicity testing of environmental chemicals.

Large scale population monitoring by cytogenetics would require vast amounts of effort for meaningful results. Computer techniques promise to assume some of this burden and thus render large scale monitoring a more practical alternative than it is now. A system recently developed at the California Institute of Technology, Jet Propulsion Laboratory and the City of Hope Medical Center, contains many of the features required by a large scale population monitoring system. One part of the system is a semi-automated slide preparation assembly which can process up to 576 specimens per day with uniform treatment. The second part of the system consists of a computer-controlled microscope which performs automatic slide search, metaphase location, and karyotype analysis under the interactive supervision of an operator. While the system was developed primarily for clinical cytogenetics, some aspects of our operating experience suggest promising approaches for population cytogenetics.

Chromosome Aberrations↗