Genetic differentiation in Hippocrepis emerus (Leguminosae): allozyme and DNA fingerprint variation in disjunct Scandinavian populations

The structure of genetic variation in disjunct Scandinavian populations of Hippocrepis emerus was studied using allozymes and DNA fingerprinting. Variation in the three native regional populations in Scandinavia was compared with that in a recently introduced population in Sweden. In contrast to the recently introduced population, the native Scandinavian isolates of H. emerus showed high levels of allozyme fixation and low levels of DNA diversity. Variation in allozymes and at DNA fingerprint loci showed closely congruent patterns of geographic variation, with pronounced differentiation between the native Norwegian and Swedish isolates of the species. The structure of genetic variation in native Scandinavian H. emerus is interpreted in terms of historical population bottlenecks and founder events during the species' postglacial immigration into Scandinavia.     

Genetic monogamy in single-male groups of acorn woodpeckers, Melanerpes formicivorus

Acorn woodpeckers have one of the most complex social systems of any bird species. Breeding units range in size from monogamous pairs to groups of 15 birds that include multiple breeding males and females as well as nonreproductive helpers-at-the-nest. Groups form when young remain at their natal nest to help their parents breed or when single-sex coalitions of siblings disperse to fill a reproductive vacancy on another territory. Plural breeding and helping behaviour are thought to be favoured through indirect fitness benefits for individuals that would otherwise be unable to breed due to a shortage of reproductive vacancies on territories with acorn stores. We report the results of multi-locus DNA fingerprinting of 51 offspring from 18 nests of 16 socially monogamous pairs of acorn woodpeckers. If socially monogamous females mate outside the pair-bond, indirect fitness benefits for cobreeders and helpers will be significantly reduced. Monogamous pairs accounted for all but one of the 51 offspring we tested; the single exception was apparently sired by the putative father, but the putative mother was excluded from maternity. Our results indicate that individuals remaining on their natal territories as helpers are generally the genetic offspring of the pair they help. They also suggest that single-sex coalitions offspring dispersing together from nests of socially monogamous pairs will be full-siblings.     

Resolving genetic relationships with microsatellite markers: a parentage testing system for the swallow Hirundo rustica

Eight polymorphic microsatellite markers from the swallow were isolated and characterized. Extraordinary variability was revealed at the HrU6 locus with 45 different alleles scored among 46 unrelated individuals. The probability that the same genotype combination would occur in two random and unrelated individuals at six selected loci was as low as 1.3 × 10^-8 and the combined exclusion probability was 0.9996. Stable Mendelian inheritance was observed in about 1000 meioses. No significant linkage was revealed and for almost all combinations of marker-pairs, linkage closer than 5 cM could be excluded. At two loci, null (nonamplifying) alleles were encountered. Thirteen (30%) extra-pair offspring were identified in 5 (56%) broods when applying the marker set on a nearly complete swallow colony. We were able to identify a single male from the other families in the colony as the most likely father for nine of the 13 extra-pair offspring.     

Multiple paternity in the red-eyed treefrog Agalychnis callidryas (Cope)

DNA fingerprinting of tadpoles from two different ‘one female-two male’ matings of the red-eyed treefrog, Agalychnis callidryas, revealed multiple paternity of offspring. Offspring were assigned paternity based on bands shared with the putative father, but not shared between putative fathers or with the mother. Paternity was split 44/56% and 36/64% in two matings. These results do not support a hypothesis of sperm priority in access to unfertilized eggs by primary males. Multiple paternity may be commonplace in species of anurans with matings by multiple males.     

Natal dispersal and genetic structure in a population of the European wild rabbit (Oryctolagus cuniculus)

A combination of behavioural observation, DNA fingerprinting, and allozyme analysis were used to examine natal dispersal in a wild rabbit population. Rabbits lived in territorial, warren based social groups. Over a 6-year period, significantly more male than female rabbits moved to a new social group before the start of their first breeding season. This pattern of female philopatry and male dispersal was reflected in the genetic structure of the population. DNA fingerprint band-sharing coefficients were significantly higher for females within the same group than for females between groups, while this was not the case for males. Wrighfs inbreeding coefficients were calculated from fingerprint band-sharing values and compared to those obtained from allozyme data. There was little correlation between the relative magnitudes of the F-statistics calculated using the two techniques for comparisons between different social groups. In contrast, two alternative methods for calculating F_ST from DNA fingerprints gave reasonably concordant values although those based on band-sharing were consistently lower than those calculated by an ‘allele’ frequency approach. A negative F_IS value was obtained from allozyme data. Such excess heterozygosity within social groups is expected even under random mating given the social structure and sex-biased dispersal but it is argued that the possibility of behavioural avoidance of inbreeding should not be discounted in this species. Estimates of genetic differentiation obtained from allozyme and DNA fingerprint data agreed closely with reported estimates for the yellow-bellied marmot, a species with a very similar social structure to the European rabbit.     

Spawning patterns in the three-spined stickleback (Gasterosteus aculeatus L.): an evaluation by DNA fingerprinting

We analysed a random sample of 10 three-spined stickleback nests by DNA fingerprinting. DNA from the guardian male and a random subsample of LO fry per nest were probed with pYNZ 132, a human single-locus probe for VNTR-loci (variable number of tandem repeats). On average this probe produced DNA fingerprints of 12 scoreable bands. By comparing the bands present in each individual, we calculated band sharing indices (BSIs) between the guardian male and its fry. The BSls varied between 0.40 and 0.77 with an average (± S.D.) of 0.59 ± 0.09. We therefore conclude that the guardian male was the true father of the fry in all these nests. Once the paternal bands in each fry were determined, we compared the maternal bands among the fry of each nest. Based on the BSIs obtained with these comparisons, we found that one guardian male enticed three females to spawn in its nest, six enticed two females and three enticed one female.     

A new DNA profiling system for cell line identification for use in cell banks in Japan

Summary Using the polymorphic DNA probes, ChdTC-15, ChdTC-114, pYNH24, and λTM-18, a DNA profiling system was developed that verified identities of individual cultured cell lines collected in the Japanese cell banks, JCRB, RCB, and IFO. These highly polymorphic DNA probes include both VNTR (Variable Number of Tandem Repeats) sequences and substantial lengths of unique regions. In the mixed probe system, several distinct bands from four to eight can be used for cell line identification. These bands were widely spread in a range of molecular sizes, and were stable and reproducible under stringent conditions of Southern blot hybridization. Because the DNA profile was specific for each individual human cell line, it is useful not only to authenticate many existing cultured cell lines but also to monitor their identity during propagation in a laboratory, and to confirm newly established lines as unique.     

Absence of repetitive DNA sequences associated with sex chromosomes in natural populations of the Trinidad guppy (Poecilia reticulata)

The genus Poecilia has been widely studied as a model for the evolution of sex chromosomes. In the course of molecular studies on population genetic structure and sexual selection in the Trinidad guppy, we examined our preparations for male-linked, repetitive DNA polymorphisms. We have not obtained any evidence of male-specific polymorphisms, in contrast to an earlier study. Our results have significant implications for theories on the evolution of sex chromosomes.Correspondence to: F. Breden     

Genetic diversity inferred from AFLP fingerprinting in populations of Onosma echioides (Boraginaceae) from serpentine and calcareous soils

Abstract

Onosma echioides is a non-obligate serpentinophytic borage occurring discontinuously on calcareous and serpentine outcrops at the northwest limit of its range. Mean concentrations of Ca, Mg and heavy metals in root and shoot samples of eight populations from the two soil types were first determined. Subsequently, the genetic polymorphism of the same accessions was estimated by means of Amplified Fragment Length Polymorphism (AFLP) fingerprinting technique. Root and shoot samples from serpentine outcrops showed higher levels of Ni, Cr and Mg, and lower Ca/Mg ratios compared with those from calcareous soils. Based on 353 polymorphic AFLP bands, the two edaphic groups of populations showed comparable levels of genetic diversity. A remarkable genetic differentiation between populations and a high level of within-population genetic variance were found. Results of Mantel's test supported a significant correlation between genetic and geographical distances, while no difference in relation to the edaphic factor was detected. Molecular data suggested isolation as the key factor shaping the infraspecific genetic structure of O. echioides, which may be in relation with the short-distance, zoochorous systems of seed dispersal and pollination of this species.