ABSTRACT
Conservation biology needs sound biological information in order to maintain biological diversity in the face of the current rate of loss. An important component of the information needed is the level of genetic diversity within and between populations, especially for those species faced with exposure to environmental stressors. We applied multilocus DNA profile analysis (highly variable number tandem repeats [HVNTR] and randomly amplified polymorphic DNA [RAPD] techniques) and allozyme analysis to test whether individuals from historically degraded sites display levels of genetic diversity different from individuals taken from reference sites. Four Lake Erie tributaries, two impacted and two reference sites, were the sources of brown bullhead (Ameiurus nebulosus) samples. Pairwise comparison of the sampled populations demonstrated an association of decreased genetic diversity with exposure of brown bullhead to stressors using both RAPD and HVNTR analysis.
Subject(s)
Conservation of Natural Resources , DNA Fingerprinting , Environmental Pollutants/adverse effects , Genetic Variation , Ictaluridae/genetics , Animals , Biomarkers/analysis , Random Amplified Polymorphic DNA Technique , Tandem Repeat Sequences/geneticsABSTRACT
In recent years microsatellite marker applications in various disciplines increased rapidly. Microsatellites are characterized as independent and highly variable markers most noted for their usefulness and popularity among researchers. Microsatellites can be constructed in-house from a partial genomic library, ordered from a vendor, or "borrowed" from a species that is closely related to the target species. Microsatellite application in natural populations can reveal present as well as historical impacts of stressors to particular population.
Subject(s)
Environmental Pollutants/adverse effects , Gene Library , Genetics, Population , Microsatellite Repeats/genetics , Animals , Genetic Markers , Genetic VariationABSTRACT
Three management systems (winter, spring, and late summer) distinguished by season of lambing and management practices were compared for litter size born and weaned and growth and carcass characteristics of lambs. Three sire breeds (Cheviot, Rambouillet, and Suffolk) and three dam breeds (Florida Native, Native-X, and Synthetic-X) were used in 698 matings over a 3-yr period. System affected (P < .01) litter size born. Spring lambing yielded more lambs (1.62) than winter (1.49) and late summer (1.12). The winter-born lambs were lighter but fatter (P < .05), and spring-born lambs were leaner with higher leg conformation and carcass quality scores. The late summer-born lambs were not different from spring-born lambs. Wethers had higher (P < .01) weights off test than ewe lambs (43.9 vs 42 kg) but had lower (P < .01) leg conformation scores, percentage kidney and pelvic fat, yield grade, and dressing percentages. Dam breed effects were significant (P < .05) for average preweaning daily gains with 249+/-5, 201+/-9, and 191+/-9 g for progeny of Native-X, Florida Native, and Synthetic-X, respectively. Single-born lambs had higher daily gains (P < .05) than twins in a preweaning period in all management systems and higher postweaning and lifetime daily gains for winter and spring management systems.
