Thomas Bucher

Comprehensive paternity assignment: genotype, spatial location and social status in song sparrows, Melospiza Melodia

Comprehensive, accurate paternity assignment is critical to answering numerous questions in evolutionary ecology. Yet, most studies of species with extra‐pair paternity (EPP) fail to assign sires to all offspring. Common limitations include incomplete and biased sampling of offspring and males, particularly with respect to male location and social status, potentially biasing estimated patterns of paternity. Studies that achieve comprehensive sampling and paternity assignment are therefore required. Accordingly, we genotyped virtually all males and >99% of 6‐day‐old offspring over 16 years in a song sparrow (Melospiza melodia) population and used three complementary statistical methodologies to attempt complete paternity assignment for all 2207 offspring. Assignments were highly consistent across maximum likelihood methods that used solely genotype data, and heuristic and integrated Bayesian analyses that included data describing individual locations. Sires were assigned to >99% of all genotyped offspring with ≥95% confidence, revealing an EPP rate of c. 28%. Extra‐pair sires primarily occupied territories neighbouring their extra‐pair offspring; spatial location was therefore highly informative for paternity assignment. EPP was biased towards paired territorial males, although unpaired territorial and floater males sired c. 13% of extra‐pair offspring. Failing to sample and include unpaired males as candidate sires would therefore substantially reduce assignment rates. These analyses demonstrate the integration of genetic and ecological information to achieve comprehensive paternity assignment and direct biological insight, illustrate the potential biases that common forms of incomplete sampling could have on estimated patterns of EPP, and provide an essential basis for understanding the evolutionary causes and consequences of EPP.

Male reproductive pattern in a polygynous ungulate with a slow life-history: the role of age, social status and alternative mating tactics

According to life-history theory age-dependent investments into reproduction are thought to co-vary with survival and growth of animals. In polygynous species, in which size is an important determinant of reproductive success, male reproduction via alternative mating tactics at young age are consequently expected to be the less frequent in species with higher survival. We tested this hypothesis in male Alpine ibex (Capra ibex), a highly sexually dimorphic mountain ungulate whose males have been reported to exhibit extremely high adult survival rates. Using data from two offspring cohorts in a population in the Swiss Alps, the effects of age, dominance and mating tactic on the likelihood of paternity were inferred within a Bayesian framework. In accordance with our hypothesis, reproductive success in male Alpine ibex was heavily biased towards older, dominant males that monopolized access to receptive females by adopting the ‘tending’ tactic, while success among young, subordinate males via the sneaking tactic ‘coursing’ was in general low and rare. In addition, we detected a high reproductive skew in male Alpine ibex, suggesting a large opportunity for selection. Compared with other ungulates with higher mortality rates, reproduction among young male Alpine ibex was much lower and more sporadic. Consistent with that, further examinations on the species level indicated that in polygynous ungulates the significance of early reproduction appears to decrease with increasing survival. Overall, this study supports the theory that survival prospects of males modulate the investments into reproduction via alternative mating tactics early in life. In the case of male Alpine ibex, the results indicate that their life-history strategy targets for long life, slow and prolonged growth and late reproduction.

Inbreeding coefficient and heterozygosity–fitness correlations in unhatched and hatched song sparrow nestmates

Heterozygosity–fitness correlations use molecular measures of heterozygosity as proxy estimates of individual inbreeding coefficients (f) to examine relationships between inbreeding and fitness traits. Heterozygosity–fitness correlations partly depend on the assumption that individual heterozygosity and f are strongly and negatively correlated. Although theory predicts that this relationship will be strongest when mean f and variance in f are high, few studies of heterozygosity–fitness correlations include estimates of f based on pedigrees, which allow for more thorough examinations of the relationship between f, heterozygosity and fitness in nature. We examined relationships between pedigree‐based estimates of f, multilocus heterozygosity (MLH) and the probability of survival to hatch in song sparrow nestmates. f and MLH were weakly, but significantly negatively correlated. Inbreeding coefficient predicted the probability of survival to hatch. In contrast, MLH did not predict the probability of survival to hatch nor did it account for residual variation in survival to hatch after statistically controlling for the effects of f. These results are consistent with the expectation that heterozygosity–f correlations will be weak when mean and variance in f are low. Our results also provide empirical support for recent simulation studies, which show that variation in MLH among siblings with equal f can be large and may obscure MLH–fitness relationships.

Factors Affecting Self-Reported Sexuality in Men with Obstructive Sleep Apnea Syndrome

INTRODUCTION Obstructive sleep apnea syndrome (OSAS) is known to induce erectile dysfunction and to reduce overall sexual satisfaction in affected men. Data on the effects of disease severity and other contributing factors such as the age of the patient are missing. AIM To compare self-reported sexuality in men with newly diagnosed sleep apnea with a group of disease-free men, and to evaluate the impact of disease severity and age on the response pattern. MAIN OUTCOME MEASURES Self-reported erectile function, desire, and frequencies for petting, tenderness, masturbation, sexual intercourse, and overall satisfaction with sexuality over a recall period of 3 months. METHODS A prospective survey in men admitted to a multidisciplinary sleep center using a standardized validated German questionnaire. RESULTS One hundred-sixteen men 51.1 +/- 11.4 years (mean +/- standard deviation) with OSAS (OSAS+) and 42 men age 46.6 +/- 13.7 years without OSAS (OSAS-) completed the survey. OSAS+ men were older (P = 0.01) and more often divorced (P = 0.048). OSAS was significantly associated with erection problems (P = 0.024) and decreased overall sexual satisfaction (P = 0.04). In contrast disease severity did affect masturbation frequency only (P = 0.02), whereas patient age affected erection (P = 0.001), and the desire for tenderness (P = 0.02) and intercourse (P = 0.0003). CONCLUSION Patient age might be a more important factor affecting sexuality in men with sleep apnea than the disease severity. Future studies assessing sexuality in men with OSAS should include age as an additional variable.

A microsatellite-based linkage map for song sparrows (Melospiza melodia)

Although linkage maps are important tools in evolutionary biology, their availability for wild populations is limited. The population of song sparrows (Melospiza melodia) on Mandarte Island, Canada, is among the more intensively studied wild animal populations. Its long‐term pedigree data, together with extensive genetic sampling, have allowed the study of a range of questions in evolutionary biology and ecology. However, the availability of genetic markers has been limited. We here describe 191 new microsatellite loci, including 160 high‐quality polymorphic autosomal, 7 Z‐linked and 1 W‐linked markers. We used these markers to construct a linkage map for song sparrows with a total sex‐averaged map length of 1731 cM and covering 35 linkage groups, and hence, these markers cover most of the 38–40 chromosomes. Female and male map lengths did not differ significantly. We then bioinformatically mapped these loci to the zebra finch (Taeniopygia guttata) genome and found that linkage groups were conserved between song sparrows and zebra finches. Compared to the zebra finch, marker order within small linkage groups was well conserved, whereas the larger linkage groups showed some intrachromosomal rearrangements. Finally, we show that as expected, recombination frequency between linked loci explained the majority of variation in gametic phase disequilibrium. Yet, there was substantial overlap in gametic phase disequilibrium between pairs of linked and unlinked loci. Given that the microsatellites described here lie on 35 of the 38–40 chromosomes, these markers will be useful for studies in this species, as well as for comparative genomics studies with other species.

Microsatellite primers for the four Galápagos mockingbird species (Mimus parvulus, Mimus macdonaldi, Mimus melanotis and Mimus trifasciatus)

Nineteen di‐ and tetranucleotide and one trinucleotide microsatellite DNA markers were isolated from the Galápagos mockingbird (Mimus parvulus) and tested for cross‐species amplification in the other three mockingbird species in the Galápagos. In addition, primers for two microsatellite loci previously developed for Mimus polyglottos were redesigned to obtain shorter amplification fragments. The number of alleles per locus and species ranged from 1 to 8, and expected heterozygosity varied from 0.0 to 0.809. These microsatellite markers will be useful to study levels of inbreeding in different island populations.

Microsatellite DNA markers for the snow vole (Chionomys nivalis).

A total of 14 dinucleotide microsatellite loci were characterized in the snow vole (Chionomys nivalis). Allelic polymorphism across all loci and 28 individuals representing a single population in the Swiss Alps was high (mean = 10.1 alleles). No significant linkage disequilibrium between pairs of loci and no departure from Hardy–Weinberg equilibrium were found. These loci will be useful for describing mating systems and population structure and to investigate the genetic consequences of a species living in a highly fragmented habitat.

Development of microsatellite loci in the European Dipper, Cinclus cinclus

Eighteen polymorphic microsatellite DNA loci were isolated in the Central European subspecies of the European Dipper (Cinclus cinclus aquaticus). The loci were tested for polymorphism using a test panel of 24 breeding birds. Numbers of alleles ranged from 2 to 21 per locus and expected heterozygosities varied between 0.47 and 0.83. Two loci (Cici10 and Cici12) proved to be Z-linked. Some pairs of loci exhibited significant linkage disequilibrium but not the two loci that are located on the Z-chromosome. This pattern suggests that demographic effects rather than physical linkage are likely responsible for the observed levels of linkage disequilibrium. These loci will be useful for applied conservation projects and for investigations of the dispersal and mating patterns of European and other dippers.