MOLECULAR EVOLUTION IN THE FISH GENUS MORONE.
Item
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Title
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MOLECULAR EVOLUTION IN THE FISH GENUS MORONE.
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Identifier
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AAI8801776
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identifier
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8801776
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Creator
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WIRGIN, ISAAC I.
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Contributor
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Joseph Grossfield
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Date
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1987
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, General
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Abstract
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We have used restriction endonuclease analysis of mitochondrial DNA (mtDNA), isoelectric focusing of eye lens proteins, and isozyme analysis as means to quantify the extent of genetic divergence in the genus Morone, particularly in striped bass. One of our primary goals was to detect an innate genetic marker which could be used in striped bass stock discrimination. Proteins proved relatively monomorphic with the exception of age related structural changes in eye lens proteins. Striped bass mtDNA also exhibited extremely low levels of base sequence diversity within and among the populations examined. Striped bass harbor the lowest level of conspecific mtDNA divergence of any vertebrate species examined in depth to date (p = 0.0004). Yet despite this lack of base substitutions, geographically partitioned mtDNA length polymorphisms were observed. All populations examined were polymorphic for length variation. Among all populations studied, six different lengths of the mtDNA molecule were detected. In addition, minor length variants ({dollar}<{dollar}25 base pairs) were observed in the Atlantic coastal stock. By considering these two forms of mtDNA length variation, the Hudson stock was clearly differentiated from an aggregate Chesapeake population. This information also permitted us to distinguish an upper from lower Chesapeake Bay population. Rare base substitutions and minor length variants detected exclusively by four-base-cutters allowed us to unambiguously identify ancestry of a moderate percentage (25%) of individual mid-and-upper Chesapeake Bay striped bass. A single Xba 1 base substitution allowed us to identify some striped bass of Gulf of Mexico ancestry in remnant mixed populations. Striped bass exhibit extremely high levels of heteroplasmy ({dollar}\sp{lcub}\sim{rcub}{dollar}20%) for length variation in all spawning systems. The meager levels of base sequence diversity we have reported in striped bass, was explained on the basis of its life history pattern and recent geological events. The unusual mode of mtDNA change in striped bass, and in the Morone species in general, must be viewed as a taxon specific phenomenon.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Biology
