Melvin L. Beck

Karyological analysis of Ctenopharyngodon idella, Aristichthys nobilis, and their F1 hybrid

Abstract Ctenopharyngodon idella (grass carp) and Aristichthys nobilis (bighead carp) have a diploid chromosome number of 48 with no acrocentric chromosomes. The hybrid of these species is triploid with 72 chromosomes. The frequencies of metacentric and submetacentric chromosomes suggest that the hybrid receives two maternal and one paternal set of chromosomes.

Hematologic and enzymatic analysis of Ctenopharyngodon idella × Hypophthalmichthys nobilis F1 hybrids

1. Erythrocyte counts, hemoglobin concentrations and hematocrit values were determined for diploid and triploid Ctenopharyngodon idella X Hypophthalmichthys nobilis hybrids and the parental species. 2. Comparisons of diploid and triploid hybrids with the parental species revealed low erythrocyte counts for triploids, high mean corpuscular hemoglobin values for triploids, elevated hematocrits for diploids and triploids and similar hemoglobin concentrations for all fish. 3. Alkaline phosphatase, aldolase, and lactate dehydrogenase specific activities were determined spectrophotometrically. Levels of specific activity of these enzymes in the hybrids were consistently elevated above that of the parental species. These higher levels of enzyme activities in hybrids were probably the result of a breakdown in gene regulation.

ZZW autotriploidy in a Blue-and-Yellow Macaw

We describe genome size (nuclear DNA content), and cellular and nuclear dimensions of erythrocytes in a triploid Blue-and-Yellow Macaw (Ara ararauna) and its diploid parents. The genome size of the triploid (4.23 pg) was 1.5 times greater than the genome size of the mother (2.80 pg) and the father (2.89 pg). The sex chromosome composition was ZZW, and was predicted correctly based on the genome size of the parents. Erythrocytes of the triploid were significantly larger than the erythrocytes of the parents. Because polyploidy has been reported only in one other family of birds (Phasianidae), the parrots and their relatives might prove to be useful in the study of avian triploidy.

Biochemical genetics of the raccoon, Procyon lotor

Polyacrylamide gel electrophoresis was used to examine genetic variation in Procyon lotor from six states in the southeastern United States. Allozymic variation of 12 genetic loci was analyzed from nine populations of P. totor. Five loci were found to be polymorphic with the remaining seven loci being fixed for the same gene in all populations. Mean heterozygosity (H ~1.4%) was found to be relatively low for a mammal. In all samples examined, one or two loci were major contributors to the observed heterozygosity. P. lotor was found to be genetically homogeneous over that portion of the range investigated.

Heterochromatin in mitotic chromosomes of theVirilis species group ofDrosophila

The amount of heterochromatin in the genome of ten members of thevirilis species group was determined as the length of C-band chromosome material relative to the total karyotype length. Thevirilis phylad (Drosophila virilis, D. novamexicana, D. americana americana, andD. americana texana) has significantly greater amounts of heterochromatin in the genome than do members of the montana phylad (D. montana, D. lacicola, D. flavomontana, D. borealis, D. ezoana, D. littoralis). Thus, the significant karyotypic change accompanying diversification of these species has involved reduction in their total constitutive heterochromatin. These changes have apparently involved reductions in the amount of centromeric heterochromatin in the autosomes.

Ploidy of Hybrids between Grass Carp and Bighead Carp Determined by Morphological Analysis

Abstract Twenty-six morphological and meristic characters of diploid and triploid hybrids between female grass carp, Ctenopharyngodon idella and bighead carp Hypophthalmichthys nobilis were analyzed by discriminant-function analysis. Twelve characters were useful in distinguishing between diploids and triploids. When these 12 characters were subjected to discriminant-function analysis, 97% of the hybrids were correctly classified as either diploid or triploid. No single character allowed diploids to be distinguished from triploids. Triploid hybrids had fewer morphological abnormalities than did diploid hybrids, possibly because triploid hybrids had two sets of chromosomes from the same species. Received March 5, 1983 Accepted August 8, 1983

Ammoniacal silver staining of nucleolar organizer regions in four species of Bufo

STEJNEGER, L. 1907. Herpetology of Japan and adjacent territory. Bull. U. S. Nat. Mus. 58:47-161. STORM, R. M. 1947. Eggs and young of Aneidesferreus. Herpetologica 4:60-62. TILLEY, S. G. 1972. Aspects of parental care and embryonic development in Desmognathus ochrophaeus. Copeia 1972:532-540. VANDEL, A., AND BOUILLON, M. 1959. La reproduction du protee (Proteus anguineus), C. R. Acad. Sci. Paris 248:1267-1272.

Using Morphologic Characters to Identify Peromyscus in Sympatry

Abstract To assess the usefulness of morphologic characters in identifying deer mice (Peromyscus maniculatus), white-footed mice (P. leucopus) and cotton mice (P. gossypinus) in sympatry, cranial and external measurements were recorded for two groups of these rodents. Each group contained individuals of the three species. One assemblage represented known individuals (species identifications verified using electrophoretic techniques) and the other unknowns (species identification not verified; test group). With the known group, we developed a system of identification based on selected morphologic features. These features were used to determine the identification of individuals in the test group. Following identification, individuals identified in the test group were confirmed using electrophoretic procedures. Two characters (greatest length of skull and length of hindfoot) separated 100% and 91% of P. gossypinus in the known group and 94.6% and 98% in the test group, respectively. A single external metric (tail length/total length) correctly classified 95% of P. maniculatus in both the known and test groups. A suite of four cranial (greatest length of skull, length of nasal, post-palatal length and length of diastema) and one external character (length of tail) correctly classified all of the individuals in the initial group and 90%, 91% and 100% of P. maniculatus, P. leucopus and P. gossypinus, respectively, in the test group. We concluded that morphologic characters can be used to accurately detect species of Peromyscus in sympatry.

Genetic variation and differentiation in Armadillidium vulgare (Isopoda: Oniscoidea)

Genetic variation was examined with polyacrylamide and starch gel electrophoresis at 22 loci in 8 populations of Armadillidium vulgare. Polymorphism was observed at 9 loci, and the average heterozygosity was 3.0%. Heterozygosity was low when compared to most invertebrates but was similar to that reported for certain decapods. A significant heterozygote deficiency occurred in most populations of A. vulgare and considerable genetic differentiation was observed among isopod populations.

Temporal and Spatial Genetic Variability in White-tailed Deer (Odocoileus virginianus)

Starch-gel electrophoresis was used to assess temporal and spatial genetic variation in populations of white-tailed deer (Odocoileus virginianus) in western Tennessee. Samples of liver and kidney obtained from animals at five localities during 1985–1992 were analyzed at 11 loci known to be polymorphic in white-tailed deer. There were minimal significant differences in allelic frequencies between sexes and among age groups for each year at each locality and among years at each locality with ages and sexes combined. No significant difference occurred among mean values of heterozygosity. A heterozygote deficiency was detected in white-tailed deer populations from western Tennessee and could reflect limited inbreeding but was more likely due to Wahlund effects. Limited temporal variation occurred among years within a locality and indicated a stasis in terms of minimal genetic drift and harvest effects on genetic structure of the populations. Herd origin, stocking history of populations, and gene flow were probable causes of spatial heterogeneity in deer populations in western Tennessee.