Microsatellite evidence for monogamy and sex-biased recombination in the Western Australian seahorse Hippocampus angustus

Four polymorphic microsatellite loci were used to assess biological parentage of 453 offspring from 15 pregnant males from a natural population of the Western Australian seahorse Hippocampus angustus . Microsatellite genotypes in the progeny arrays were consistent with a monogamous mating system in which both females and males had a single mate during a male brooding period. Multilocus genotypes implicated four females in the adult population sample as contributors of eggs to the broods of collected males, but there was no evidence for multiple mating by females. Based on genotypic data from the progeny arrays, two loci were linked tightly and the recombination rate appeared to be ≈ 10-fold higher in females than in males. The utility of linked loci for parentage analyses is discussed.     

Reply to R. H. Abbott

IN our article in Nature last year¹ we showed that, after a step change of length imposed during tetanic contraction, the early tension recovery varies in speed according to the size and direction of the step, being slowest in large stretches and fastest in large releases. Abbott² now proposes that this variation is due not to a change of time scale of a single process but to a change in the relative amplitudes of two exponentially decaying components each of which has a fixed time constant. He shows that the records in Fig. 2 of ref. 1 can be approximately fitted in this way and concludes that “either the results are not typical or the mathematical theory put forward by Huxley and Simmons is not correct”.     

Brood adoption and deceit among African Marsh Harriers Circus ranivorus

Complete adoption of unrelated broods by foster parents is surprisingly common among birds and the behaviour appears to be maladaptive in several species. In a small, marked, southern African population of African Marsh Harriers Circus ranivorus, studied over 4 years, a young male took over the complete parenting (provisioning and defence) of an unrelated brood, and several times fed the brood in preference to the soliciting maternal parent. This female then deserted and deceitfully courted (out of season) a third male, whose provisioned food she took to feed to her own young. Since the adopting male retained the territory and bred successfully for at least two further years, he suffered no expected loss in fitness and hence this case of fostering was neither maladaptive nor apparently altruistic.     

Identification of physicochemical selective pressure on protein encoding nucleotide sequences

Background  

Statistical methods for identifying positively selected sites in protein coding regions are one of the most commonly used tools in evolutionary bioinformatics. However, they have been limited by not taking the physiochemical properties of amino acids into account.     

ATMOSPHERIC AND UNDERWATER PROPAGATION OF BULLFROG VOCALIZATIONS

ABSTRACT

Male bullfrogs vocalize while partially submerged in shallow freshwater ponds. This imposes two potential propagation pathways, atmospheric and underwater, on transmission of their communication sounds. Propagation of pure tones, amplitude modulated (AM) broadband noise and natural calls was measured in air and underwater at three bullfrog breeding sites. In air, propagation losses were consistent with spherical spreading. No excess attenuation was observed for any tone frequency at any site. Both temporal envelope modulations and spectral cues are available to conspecific receivers at biologically realistic distances. The bullfrog's advertisement call is thus well adapted for transmission in air at the air/water interface. Underwater signal propagation differed at the three sites, consistent with substrate effects. Tone propagation showed the high-pass frequency window characteristic of shallow water. Broadband signals underwent propagation losses greater than expected by cylindrical spreading. Modulations of the envelope of natural calls remained discernible at distances where frequency-dependent propagation losses distorted the shape of the spectrum. Measurements of the propagation of the advertisement call emitted by a chorusing frog at the air/water interface confirm that periodicity cues embedded in the envelope are available to receivers both in air and underwater. High frequency cues available underwater overlap the maximal hearing sensitivity of larval conspecifics (tadpoles).     

Application of DNA barcodes in Hedyotis L.(Spermacoceae, Rubiaceae)

The potential application of DNA barcodes of plastid (matK, trnH-psbA, petD, and rbcL) and nuclear (internal transcribed spacer (ITS) of rDNA) DNA regions was investigated for 25 Hedyotis taxa. The ITS showed the best species discrimination by resolving 23 of the species as exclusive lineages with no shared alleles between any of the 24 distinct species (H. Assimilis and H. Mellii are not supported as distinct species based on our molecular and morphological data). Conversely, rbcL performed the worst and only resolved 10 of the species as exclusive lineages, and 10 species with shared alleles. Using ITS has the advantage of high PCR amplification success and it provides good intra- and interspecific variation distribution patterns. The most powerful plastid markers were petD and trnH-psbA, but we could amplify and sequence trnH-psbA for only 83% of the accessions sampled. Combination of ITS and petD performed extremely well, with all 24 of the distinct species resolved as exclusive lineages and no shared alleles between any of the distinct species. We therefore recommend ITS, or a combination of ITS and petD, as the standard DNA barcode in Hedyotis, but acknowledge that there are no shared alleles between distinct species for marK and rbcL combined.     

ADVERTISEMENT CALLS OF THE TREE FROGS,HYLA ARBOREA AND HYLA SAVIGNYI (ANURA: HYLIDAE) IN TURKEY

ABSTRACT

The systematic classification of tree frogs (Hyla) inhabiting different regions of the country of Turkey is unclear. Recordings of natural advertisement calls of individual male tree frogs in different locations in Turkey were analyzed to determine variation in acoustic features that may be related to taxonomic status. Multivariate analysis of covariance showed that call duration, intercali interval and number of pulses per call varied significantly between frogs in different locales. Call duration, intercall interval, and number of pulses per call were related to air temperature. Dominant frequency differed significantly between different groups of frogs, and was temperature-independent. These data are consistent with the hypothesis that tree frogs in Turkey represent two distinct species, Hyla arborea and Hyla savignyi.     

Restriction fragment length polymorphisms in satellite DNA distinguish chromosomal races of the white-footed mouse Peromyscus leucopus

We describe a polymorphism revealed by a high-copy-number tandem repeat which serves to distinguish most individuals sampled (96%) from two chromosomal races of Peromyscus leucopus. Classical morphology, allozymes, mtDNA, and rDNA have all failed to provide fixed markers which separate these two chromosomal races. Data from P. leucopus further documents the utility of DNA polymorphisms to establish the natal origin (DNA ‘zipcodes’) of populations or individuals.