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Biomedical subjects

V M Sarich

Publications and source records attributed to V M Sarich.

At least 19 recordsLinked to original sources
PubMed1990

Schizophrenia, eye movements, and biocultural heterogeneity.

Smooth-pursuit eye-tracking dysfunction is a putative genetic trait marker for schizophrenia. In this study 88 Japanese schizophrenics from Kyushu and Okinawa were examined for the marker using precise high-resolution instrumentation: 76% of the schizophrenics from Kyushu and 89% of those from Okinawa had pursuit dysfunction. The presence of the culture-neutral smooth-pursuit marker for schizophrenia in Japan demonstrates that the etic concept "schizophrenia" is cross-culturally valid. Furthermore, the ubiquity of the marker in biologically and culturally diverse populations may indicate a limit on the extent of meaningful heterogeneity likely to be discovered within the condition.

Adult↗
PubMed1980

Mammoth albumin.

Serum albumin was detected immunologically in muscle from a mammoth that died about 40,000 years ago. Rabbits injected with ground mammoth muscle produced antibodies that react strongly with elephant albumin, weakly with sea cow albumin, and still more weakly or not at all with other mammalian albumins. Since elephant albumin elicited antibodies with the same specificity, some of the surviving mammoth albumin molecules evidently have antigenic sites identical to those on native elephant albumin. Much of the mammoth albumin has, however, undergone postmortem change. The small amount of soluble albumin extractable from mammoth muscle is heterogeneous in size, charge, and antigenic properties.

Animals↗
PubMed1978

Marmoset evolution: the molecular evidence.

We report here the results of comparative immunological and electrophoretic studies of the serum proteins of the New World monkeys. Specifically, we find that the New World monkeys share a long period of common ancestry with the Catarrhini and that the divergence between these two groups occurred some 35-40 million years ago. The extant New World monkey lineages are then seen as sharing a long period of common ancestry subsequent to that divergence, with their radiation beginning in the early Miocene. We see seven distinct lineages stemming from this radiation: (1) Aotus, (2) Callicebus, (3) Cebus, (4) Saimiri, (5) Ateles-Lagothrix-Alouatta, (6) Pithecia-Cacajao and (7) Callimico-Callimico with Cebuella-Saguinus-Leontideus. Within those Ateles with Lagonthrix, and Callimico with Callithrix-Cebuella form further subgroups. The marmoset radiation appears to have begun some 7-10 million years ago.

Animals↗
PubMed1977

Rates, sample sizes, and the neutrality hypothesis for electrophoresis in evolutionary studies.

It is shown that electrophoretic genetic distance estimates are highly correlated with albumin immunological distances between the same pairs of species. The bimodality of rates of electrophoretic differentiation at various loci is then documented and the electrophoretic clocks involved are calibrated. The differences between the systematics and population genetics uses of electrophoretic data are then discussed. Finally, a direct electrophoretic test of the neutral alleles hypothesis is presented and exemplified on a set of Thomomys bottae-umbrinus data.

Alleles↗
PubMed1974

Two types of molecular evolution. Evidence from studies of interspecific hybridization.

To assess the significance of macromolecular sequence differences among species, we compared the serum albumins of 81 pairs of vertebrate species capable of producing viable hybrids. Micro-complement fixation experiments showed that the average difference between the albumins within such pairs was only 3 immunological distance units for placental mammals (31 pairs), but 36 units for frogs (50 pairs). Albumin immunological distance is strongly correlated with other measures of genetic distance, including those made with DNA annealing techniques. It therefore seems likely that mammalian species pairs capable of hybridization are far more similar at the macromolecular sequence level than is the case for most hybridizable frogs. We think the most likely explanation for the marked molecular restriction on hybridization among mammals is that the ratio of regulatory evolution to protein evolution is higher for mammals than for frogs. Mammals may have experienced unusually rapid regulatory evolution; indeed, this could be the factor responsible for their unusually rapid anatomical evolution.

Amino Acid Sequence↗
PubMed1974

The importance of gene rearrangement in evolution: evidence from studies on rates of chromosomal, protein, and anatomical evolution.

We have compared the relative rates of protein evolution and chromosomal evolution in frogs and mammals. The average rate of change in chromosome number has been about 20 times faster in mammals than in frogs. Whereas it takes only 3.5 million years, on the average, for a pair of mammal species to develop a difference in chromosome number, the corresponding period for frogs is 70 million years. In contrast, the rate of protein evolution in mammals has been roughly equal to that in frogs. The rapid rate of gene rearrangement in mammals parallels both their rapid anatomical evolution and their rapid evolutionary loss of the potential for interspecific hybridization. Thus, gene rearrangements may be more important than point mutations as sources for evolutionary changes in anatomy and way of life.

Adaptation, Biological↗
PubMed1969

A molecular time scale for human evolution.

We discuss published molecular evidence concerning the relationship of man to African apes and Old World monkeys. Quantitative comparisons of their serum albumins, transferrins, hemoglobins, and DNA show that man is genetically much more similar to the African apes than to the Old World monkeys. The amino acid sequences of hemoglobins from humans, chimpanzees, gorillas, and rhesus monkeys are consistent with the hypothesis that the probability of an amino acid substitution occurring in a given interval of time is the same for every hemoglobin lineage. This allows the use of these data as a hemoglobin evolutionary clock, just as we have previously done with the albumins. It is shown that concordance exists between the hemoglobin and albumin results and that both support the suggestion that the human lineage diverged from that leading to the African apes far more recently than is generally supposed. Considering both the albumin and hemoglobin data, we would set the most probable date at 4 to 5 million years.

Amino Acid Sequence↗