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 [1];  [2]
  1. Savannah River Ecology Laboratory, Drawer E Aiken SC 29801
  2. Department of Genetics, University of Georgia, Athens GA 30602
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Journal Article: Publisher's Accepted Manuscript
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Additional Journal Information:
Journal Volume: 41; Journal Issue: 1; Related Information: CHORUS Timestamp: 2017-10-20 16:49:19; Journal ID: ISSN 0014-3820
Country of Publication:
United States

Citation Formats

Lamb, Trip, and Avise, John C. MORPHOLOGICAL VARIABILITY IN GENETICALLY DEFINED CATEGORIES OF ANURAN HYBRIDS. United States: N. p., 2017. Web. doi:10.1111/j.1558-5646.1987.tb05778.x.
Lamb, Trip, & Avise, John C. MORPHOLOGICAL VARIABILITY IN GENETICALLY DEFINED CATEGORIES OF ANURAN HYBRIDS. United States. doi:10.1111/j.1558-5646.1987.tb05778.x.
Lamb, Trip, and Avise, John C. 2017. "MORPHOLOGICAL VARIABILITY IN GENETICALLY DEFINED CATEGORIES OF ANURAN HYBRIDS". United States. doi:10.1111/j.1558-5646.1987.tb05778.x.
author = {Lamb, Trip and Avise, John C.},
abstractNote = {},
doi = {10.1111/j.1558-5646.1987.tb05778.x},
journal = {Evolution},
number = 1,
volume = 41,
place = {United States},
year = 2017,
month = 5

Journal Article:
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This content will become publicly available on May 31, 2018
Publisher's Accepted Manuscript

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  • The present report focuses on novel animal models of male infertility: genetically defined mice bearing single-gene mutations that induce infertility. The primary goal of the investigations was to identify the reproductive defects in these mutant mice. The phenotypic effects of the gene mutations were deciphered by comparing the mutant mice to their normal siblings. Initially testicular steroidogenesis and spermatogenesis were investigated. The physiologic markers for testicular steroidogenesis were steroid secretion by testes perifused in vitro, seminal vesicle weight, and Leydig cell histology. Spermatogenesis was evaluated by the enumeration of homogenization-resistant sperm/spermatids in testes and by morphometric analyses of germ cellsmore » in the seminiferous epithelium. If testicular function appeared normal, the authors investigated the sexual behavior of the mice. The parameters of male sexual behavior that were quantified included mount patency, mount frequency, intromission latency, thrusts per intromission, ejaculation latency, and ejaculation duration. Females of pairs breeding under normal circumstances were monitored for the presence of vaginal plugs and pregnancies. The patency of the ejaculatory process was determined by quantifying sperm in the female reproductive tract after sexual behavior tests. Sperm function was studied by quantitatively determining sperm motility during videomicroscopic observation. Also, the ability of epididymal sperm to function within the uterine environment was analyzed by determining sperm capacity to initiate pregnancy after artificial insemination. Together, the experimental results permitted the grouping of the gene mutations into three general categories. They propose that the same biological markers used in the reported studies can be implemented in the assessment of the impact that environmental toxins may have on male reproduction.« less
  • The authors have defined a radiation hybrid panel for Xq11-q22 characterized with 20 DNA markers and shown how the panel can be used in conjunction with Alu-PCR and a gridded X-specific cosmid library to isolate cosmids from a preselected subregion. They used Alu-PCR products derived from two radiation hybrids, IHB2-B30 and IHB1-A12, sharing a segment in proximal Xq13.1, containing DXS453 to CCG1, as the only human component in common. Used as probes, these Alu-PCR products identified 39 cosmids on the gridded X-cosmid libraries that were positive for both probes. The target specificity of the derived cosmids was very high, 11more » of 13 cosmids tested mapped to the region of fragment overlap in the hybrids, as was determined by two translocation breakpoints bordering most of the target interval. Accounting for a redundancy of four in the libraries, the isolated 39 cosmids should correspond to about 10 independent loci derived from the region of fragment overlap defined by these radiation hybrids. In addition, a subset of five radiation hybrids having breakpoints in the target region could be used to further subdivide the 11 cosmids into an ordered set of five submapping intervals of Xq13.1.« less
  • Interspecific hybrids between Parthenium argentatum, the guayule rubber plant, and P. fruticosum var. fruticosum were evaluated for their potential rubber content and quality. Fifteen-mo-old field-grown plants of P. fruticosum var. fruticosum measured four times more in height and spread than those of P. argentatum, but contained less than 0.05% rubber of low mol wt. Parthenium argentatum showed 2% rubber content, with a mol wt of about one million. Resin contents varied little among parents or hybrids. The same age F/sub 1/ hybrids were intermediate in height and spread and had low rubber content, but showed presence of high mol wtmore » rubber like the guayule parent. This indicates that high mol wt rubber is expressed over the low mol wt rubber in F/sub 1/ hybrids. Despite low rubber content but favorable biomass production, F/sub 1/ hybrids revealed irregular meiotic chromosome behavior and low pollen and seed germination. These results suggest that interspecific F/sub 1/ hybrids may be used in backcross programs to increase biomass and rubber content in guayule.« less
  • The effects of polyploidy on 18 morphological and fertility characters were studied in six isogenic Pennisetum americanum (L.) Leeke x P. purpureum Schum, triploid (3x) and hexaploid (6x) clonal pairs. Four of the characters, inflorescence length and width, floret length, and flag leaf length increased in size for all clones with an increase in ploidy as a result of a dosage effect. Pollen diameter and stainability increased due to a more regular meiosis in the hexaploid (AAA'A'AB) compared to the triploid (AA'B) resulting in functional pollen grains. Differential responses to polyploidy among clones were observed for 12 plant characteristics: stomatalmore » length and frequency on both abaxial and adaxial surfaces, growth rate, tiller number per plant, plant height, stem thickness, days to flowering, flag leaf width, spikelet number per 5 cm inflorescence, and florets per spikelet. The different responses by clones are probably due to any one or combination of a dosage effect, gene number controlling a character, genotype of plant, and gene action and interaction both within and between the A and B genomes. This investigation showed the importance of studying a number of different genotypes when determining the effect of an increase in ploidy level on plant characters.« less