Minisatellite DNA Fingerprinting Research Articles

Extrapair fertilization and genetic similarity of social mates in the Mexican jay

Inbreeding depression should favor the ability of females to avoid inbreeding or minimize its effects. We tested for a relationship between genetic similarity of social pairs and the occurrence of extrapair fertilization (EPF) in the Mexican jay (Aphelocoma ultramarina). Multilocus minisatellite and microsatellite DNA fingerprinting was used to detect extrapair young and measure genetic similarity between social parents. We found that 12 of 31 (39%) nests had at least one EPF and 15 of 93 (16%) young were the result of EPF. The mean DNA fingerprinting band sharing score between social mates who had at least one EPF was significantly higher than the mean band sharing score between mates who did not (0.35 versus 0.25). The mean band sharing score for non-EPF dyads (0.25) was similar to the background band sharing among nonrelatives (0.23). The mean band sharing score for mates that had an EPF was significantly higher than that of nonrelatives (background) and was significantly lower than that of half-siblings (0.52). Our results showed a highly significant relationship between genetic similarity of social mates and incidence of EPF.

Genetic and morphological differentiation between remnant populations of an endangered species: the case of the Seychelles White‐eye

The Seychelles White‐eye Zosterops modestus is a critically endangered species that survives in two remnant populations on the islands of Mahé and Conception. Multilocus minisatellite DNA fingerprinting and morphometric measurements were used to assess the levels of variation between these populations. Mahé White‐eyes are on average significantly larger than Conception birds, as are males compared to females. The mean level of bandsharing (c. 60%) indicates low levels of genetic variability within both populations. Bandsharing is significantly lower between populations (32%), suggesting that the two populations are genetically isolated from each other, and that one is not a subsample from the other. Both populations should therefore be considered as equally important genetic reservoirs that deserve to be safeguarded. Although each population appears locally adapted to its particular island environment, such limited differentiation is not considered of major taxonomic significance. Recombining genetic variation by mixing individuals from both populations may be beneficial for the species in view of future island transfers. This illustrates the importance of investigating differentiation between remnant populations of a threatened species to orientate future conservation and management measures.

GENETIC EVIDENCE FOR EXTRAPAIR PATERNITY IN THE TUFTED TITMOUSE

Abstract Until now, there have been no reports of extrapair parentage in Tufted Titmice (Baeolophus bicolor). During 1995–1998, we used multilocus minisatellite DNA fingerprinting to estimate paternity and degree of relatedness in eight central Ohio broods of this socially monogamous species. Our results suggest a rather low rate of extrapair fertilization in the study population; three of 34 nestlings could not be attributed to the attending male. Of the three extrapair offspring, two represented the entire brood in a nest attended by their mother and a nonparental male that appeared to be a close relative of the mother.

Genetic monogamy in Monteiro's hornbill, Tockus monteiri

Hornbills display a unique breeding habit in which the female seals herself into the nest cavity prior to egg laying and remains ensconced for most of the breeding cycle. This habit necessitates long-term sperm storage, which considerably lengthens the fertile period of the female. This in turn increases the amount of time available to females to engage in extrapair copulations. Because food delivered by the male is the primary source of energy for female maintenance, egg production, incubation, female moult and offspring provisioning, male parental investment (and thus cuckoldry) in these hornbills is extremely expensive. This combination of costly male parental care and female dependence potentially places hornbills at a critical endpoint in the spectrum of genetic promiscuity operating within pairs of socially monogamous birds. A paradigm of reproductive conflict suggests that these factors might allow males to coerce females into a state of genetic monogamy. Sperm storage, however, might allow female hornbills to thwart monopolization attempts by their mates. We used minisatellite multilocus DNA fingerprinting to analyse paternity in a Namibian population of Monteiro's hornbill, Tockus monteiri. Despite the ability of female hornbills to store sperm for long periods, we found no evidence of extrapair paternity (EPP). Although we cannot explicitly rule out a role for coercion in the evolution of the genetic monogamy we observed, the benefits of EPP appear to be devalued to the point that the reproductive interests of males and females overlap considerably. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.

Reduced genetic variation in Norwegian Peregrine Falcons Falco peregrinus indicated by minisatellite DNA fingerprinting

The Scandinavian Peregrine Falcon Falco peregrinus population went through a severe population bottleneck during the second half of the twentieth century, and was almost extinct during the 1970s. This event may have reduced the amount of genetic variation in the population. With this background, a comparative study, using multilocus, minisatellite DNA fingerprinting, was carried out on broods of the Peregrine Falcon, the Merlin Falco columbarius and the Eurasian Hobby Falco subbuteo from south‐east Norway. Band‐sharing analysis of DNA fingerprints was used to test whether broods of Peregrine Falcons showed a greater between‐nest similarity in their fingerprint profiles than did broods of the two congeneric species breeding in the same region, which have not undergone any recent population bottlenecks. The results show that broods of Peregrine Falcons were significantly more similar to each other genetically than were broods of either Merlins or Eurasian Hobbies. Furthermore, there was a positive correlation between the similarity in minisatellite DNA and the similarity in a set of 11 microsatellite loci analysed for a subset of the Peregrine Falcon samples. The correlation supports the assumption that minisatellite fingerprints provide a reliable indicator of overall genetic similarity, i.e. relatedness, between breeding pairs in the population. Hence we can conclude that broods of Peregrine Falcons were genetically more related to each other than were broods of the other two species. The high similarity in minisatellite DNA between broods indicates a loss of genetic variation in the Peregrine Falcon population caused by the bottleneck, but this explanation can only be verified through a comparative genetic study of individuals sampled before and after the bottleneck event.

Genetic monogamy in the absence of paternity guards: the Capricorn silvereye, Zosterops lateralis chlorocephalus, on Heron Island

We investigated the genetic mating system of a socially monogamous passerine bird, the Capricorn silvereye Zosterops lateralis chlorocephalus, on an island of the Great Barrier Reef. There were no cases of extrapair paternity (EPP) among 122 offspring from 53 broods detectable by minisatellite or microsatellite DNA fingerprinting. Behavioral observations of paired birds showed that this was not a consequence of efficacious paternity guards and that females did not engage in extrapair copulation (EPC). Frequency of intrapair copulations was also low, with only 14 cases observed during 199 hours of observations of the 11 focal pairs in the fertile periods of females, and this was consistent with anatomical features of the cloacal protuberance in males. In this population, young birds form life-time pair bonds soon after gaining independence but females are obviously not attempting EPC possibly to redress this early mate choice. This is despite the fact that they breed in high density with a synchronous start and asynchronous spread of laying in a protracted season and males do not positively exhibit mate guarding behavior when females are fertile. Our results support high fidelity of socially monogamous birds on islands and are consistent with the hypothesis that sexual selection is reduced where genetic variation in fitness is limited.

Extra-pair paternity in waved albatrosses.

We estimated the rate of extra-pair fertilizations (EPFs) in waved albatrosses (Phoebastria irrorata) on Isla Española, Galápagos, Ecuador, using multilocus minisatellite DNA fingerprinting. Waved albatrosses are socially monogamous, long-lived seabirds whose main population is on Española. Aggressive extra-pair copulation (EPC) attempts have been observed in the breeding colony during the days preceding egg-laying. Our genetic analyses of 16 families (single chicks and their attending parents) revealed evidence of EPFs in four families. In all cases males were the excluded parent. These data suggest that waved albatrosses have an unusually high rate of EPF relative to taxa with similar life histories. Future behavioural observations will determine the extent to which forced vs. unforced EPCs contribute to this high EPF rate.

Genetic monogamy mirrors social monogamy in the Fiordland crested penguin

Fiordland crested penguins (Eudyptes pachyrhynchus, henceforth tawaki) are restricted to the southwest coast of South Island, New Zealand where they nest in small isolated colonies of <25 pairs. Tawaki are socially monogamous and adults are philopatric: pair‐bonds last some years, both resident adults participate in brooding and feeding of young, and birds regularly return to the same nest site or colony between years. To test whether tawaki are genetically as well as socially monogamous we assessed parentage in 24 families using multilocus minisatellite DNA fingerprinting. The DNA profiles of chicks were directly attributable to the resident male and female. There was no evidence supporting intraspecific brood parasitism or extra‐pair fertilisations, although maternal attribution of one chick was ambiguous. Social monogamy appears to indicate genetic monogamy in this species.

Multilocus minisatellite DNA fingerprinting and cooperative breeding

McRae and Amos (1999) make the valuable point that, when incest has occurred in cooperatively breeding birds, multilocus minisatellite DNA fingerprinting is limited in its ability to resolve parentage. Their general point is a good one, and one that they rightly point out has not been fully appreciated in studies of cooperative breeding. We nonetheless feel that they have overemphasized the problems associated with the application of multilocus minisatellite fingerprinting, as well as the advantages of using single-locus microsatellites. The main difficulty McRae and Amos (1999) identify is that, when an offspring (I) results from an incestuous mating between a mother (M) and her son (S), it will not be possible to exclude the paternal grandfather ( F) from paternity of I, by conventional band-matching analyses. If the son’s fatherF is the dominant male in the group, he may be “assigned” paternity despite the inability to exclude the son S. This will lead to underestimates of the actual rates of incest. This is a valid point worthy of attention. However, it is premature to abandon minisatellite DNA fingerprinting in these applications in favor of microsatellites because (a) except in populations with unusually low genetic polymorphism, it will usually be possible to determine when incest has not occurred (i.e., it will be possible to exclude S when he is not the father); (b) when mother-son incest has occurred, it will often be possible to exclude F by other (bandsharing) analyses, as McRae and Amos (1999) mention (again, the exceptions will be in populations with low genetic polymorphism), and (c) the conditions of low genetic polymorphism under which (a) and (b) represent difficulties can also affect the variability of microsatellite loci. We will remark on each of these points in turn.

Forced copulation results in few extrapair fertilizations in Ross’s and lesser snow geese

Extrapair paternity varies from 0 to over 70% of young among various populations of birds. Comparative studies have suggested that this variation is related to nesting density, breeding synchrony and the proportion of extrapair copulations. We used minisatellite DNA fingerprinting to examine levels of extrapair paternity in Ross’s geese,Chen rossi, and lesser snow geese,C.caerulescens c.(hereafter snow geese) nesting in the largest known goose colony in the world. These geese have one of the highest known percentages of extrapair copulation (46–56% of all attempted copulations), and all of these appeared to be forced. Among all successful copulations, 33 and 38% were extrapair in Ross’s and snow geese, respectively. Despite the high percentage of extrapair copulations, extrapair paternity was low in both Ross’s and snow geese (2–5% of young). Extrapair paternity was not related to nest density in either species. However, in snow geese, extrapair paternity was more likely to occur in nests of females that nested asynchronously, either early or late in the season. This is one of a few reported examples of a negative relationship between extrapair paternity and breeding synchrony. Extrapair young also tended to come from eggs laid later in the clutch. Although forced extrapair copulations appear to be a relatively inefficient reproductive tactic for males, they may provide a reproductive advantage for some males.

Reproduction by subordinates in cooperatively breeding Arabian babblers is uncommon but predictable

In a genetic analysis of the mating system of cooperatively breeding Arabian babblers (Timalidae: Turdoides squamiceps), we identified which individuals in the population are breeding, and how reproductive success was distributed among group members with respect to their dominance rank, for both males and females. The population was characterized by an asymmetrical distribution of reproductive success; behaviorally dominant males produced 176 of 186 (95%) of the offspring in 44 social groups analyzed, and alpha females produced 185 of 186 (99.5%). We evaluated models of reproductive skew by examining genetic and demographic correlates of reproduction by␣subordinates. Subordinate (beta) males that sired young were more likely to be recent dispersers from their natal groups or members of newly formed groups than betas that did not reproduce. Breeding beta males had spent smaller proportions of their lives with the current alpha male and female as alphas than had beta males that did not sire young. One consequence of the linkage of dispersal with breeding in newly formed, nonnatal groups is that beta males that sired young had significantly lower genetic similarity to the alpha males in their groups (based on band-sharing coefficients using multilocus minisatellite DNA fingerprinting) than those that did not sire young. This pattern may occur generally in species in which group membership accrues both through nondispersal of young (forming groups of relatives) as well as through dispersal involving coalitions that sometimes include nonrelatives.

High levels of polymorphism detected with M13 fingerprinting probe in bird species and populations

Hypervariable minisatellite markers have widely been used in forensic, paternity, and mating system studies, and applied to population genetics of animals and plants. In birds, minisatellite DNA fingerprinting was first developed through the use of 33.15 and 33.6 poly‐core probes. To date, few studies exist where other fingerprinting probes have been used. The aim of the present analysis is to extend the use of the M13 minisatellite probe to the genetic study of natural populations of passerine and non‐passerine birds through the optimization of an easy‐to‐make procedure, in order to address questions related with the biogeography, ecology, reproductive biology, and systematics of this group. The M13 fingerprinting probe yielded multibanded fingerprints from the genomes of all species analysed, and the average number of bands was comparable with values obtained in literature using different multilocus probes. Similarity values varied according to the phylogenetic distances among taxonomic units. In Passer montanus, the analysed populations proved to be genetically distinct, and the within‐population similarity values were comparable with those obtained, using the same technique, in a congeneric species.

GENETIC VARIABILITY AND SPATIAL SEPARATION IN THE SEA PALM KELP POSTELSIA PALMAEFORMIS (PHAEOPHYCEAE) AS ASSESSED WITH M13 FINGERPRINTS AND RAPDS1

ABSTRACTPostelsia palmaeformis Ruprecht is an annual species, occuring from southern California to Vancouver Island, Canada, in upper intertidal sites exposed to extreme wave shock. Because of its limited spore dispersal, discrete and inbred populations are likely on the local scale, yet dispersal of drifting and fertile thalli raises the possibility of outbred populations on a regional scale. M13 minisatellite DNA fingerprinting and random amplified polymorphic DNA (RAPD) marks were used in a complementary fashion to investigate genetic variability among 24 individuals on scales of clusters (= coalesced holdfasts). &lt; 1 m, 10 m, 25 m, 16 km, and 250 km. Based on M13 fingerprinting, genetic relatedness within clusters was extremely high. Three of six clusters had at hast two identical individuals, and similarity values within five clusters were ≧0.90. Similarities between two of three clusters separated by &lt; 1 m were significantly higher than between cluster pairs separated by 25 m and 250 km: however, the similarity between two clusters separated by 25 m was equivalent to the similarity between two clusters separated by 250 km. Thus, genetic relatedness as determined by M13 fingerprinting generally decreased as distance increased to 25 m. Conversely, RAPD data easily discriminated populations separated by 16 and 250 km but were not useful in discriminating individuals from &lt; 1 to 25 m. Results from the complementary data sets suggest that most dispersal occurs over distances of 1–5 m, individuals within a cluster are siblings, and distinguishable biogeographic populations are present along the coast.

Sexual selection and extrapair fertilization in a socially monogamous passerine, the zebra finch (Taeniopygia gullata)

We investigated paternal exclusion rate (the percentage of young reared by a male that were not his genetic offspring), and behavioral and reproductive variables influencing this rate, in a freely breeding laboratory population of zebra finches (Tae-niopygia guttala castanotis), a socially monogamous grassfinch. Prior to the experiment, each male founder was fitted with either two red bands (creating a phenotype previously demonstrated to be attractive to females) or two green bands (unattractive to females) as part of a unique combination of four leg bands. The overall paternal exclusion rate was 28%, as determined by multilocus, minisatellite DNA fingerprinting of 278 offspring reared by 26 males and their mates. Mean exclusion rates were 16% and 40% for red- and green-banded males, respectively. Exclusion rates were directly proportional to rates of female participation in unforced extrapair copulations (UEPCs) with red-banded males that occurred when females were fertile. Rates of fertile, forced extrapair copulations (FEPCs) and fertile UEPCs involving green-banded males either failed to influence exclusion rate or varied inversely with exclusion rate, indicating that extrapair fertilization (EPF) is under female control. Effort devoted by males to seeking EPFs increased exclusion rate. Results suggest that males place greater effort into seeking fertile versus infertile EPCs and that unattractive males accrue fitness gains through high parental investment (PI), whereas attractive males benefit through decreased PI and increased allocation to EPF.

Monogamy in Leach's Storm-Petrel: DNA-Fingerprinting Evidence

We used multilocus minisatellite DNA fingerprinting to estimate the frequency of extrapair fertilizations in a population of Leach's Storm-Petrel (Oceanodroma leucorhoa) on Kent Island, New Brunswick, Canada. Leach's Storm-Petrel is a member of Procellariiformes, an order of long-lived pelagic birds characterized by long-term pairbonds, single-egg clutches, and extended periods of parental care. We found no evidence of extrapair fertilizations in 48 families (42 full families and 6 partial families consisting of the putative father and the single offspring). Thus, our results indicate that the breeding system (genetic monogamy) matches the mating system (social monogamy) in our study population, a condition that no longer can be assumed in socially monogamous bird species. Genetic monogamy in Leach's Storm-Petrels may be maintained by last-sperm precedence and frequent copulation by mates during the female's fertile period. Such tactics employed by a male may yield a high prob- ability of fertilizing the single egg laid by his mate. Received 15 June 1994, accepted 31 August

Confirmation of cooperative polyandry in the Galapagos hawk (Buteo galapagoensis)

Without genetic tests of parentage, descrip- tions of mating systems must be considered hypotheti- cal. Here we confirm the existence of cooperative polyandry in the Galapagos hawk (Buteo galapagoensis) using multilocus minisatellite DNA fingerprinting. In this species, breeding groups consist of one adult female and from one to eight males (the modal number of males is two). In polyandrous groups, all males copulate with the female and participate in the provisioning of the young. DNA samples from 66 individual hawks from ten breeding groups on the island of Santiago revealed mixed paternity in most groups. Multiple paternity was detected in five of six groups that produced two chicks in one breeding attempt (year). In addition, different males sired young in consecutive years in five of six groups in which male group membership was constant. Patterns of paternity suggest that reproductive success was randomly distributed among males within groups, with males apparently having equivalent probabilities of siring each young. Analysis of genetic similarity indi- cates that males within groups were typically not close relatives. These results demonstrate that the mating sys- tem of the Galapagos hawk is polyandrous, with rela- tively egalitarian relations among unrelated males be- longing to the same breeding group.

Paternity exclusion in a community of wild chimpanzees using hypervariable simple sequence repeats

We report the use of hypervariable simple sequence repeat (SSR) nuclear loci to study paternity in a community of wild chimpanzees (Pan troglodytes schweinfurthii) in Gombe National Park, Tanzania. All 43 living members of a habituated community were sampled and 35 were genotyped at 8 SSR loci using DNA amplified from hair. Paternity exclusions were performed for 25 chimpanzees including 10 for whom the mother was also genotyped. In each case 12-20 males were potential fathers based on their age and/or direct observation of sexual behaviour. 179 tests involving potential father/offspring combinations were performed. In four cases the data permit the probable identification of the previously undetermined father; these are the first such determinations for free-ranging chimpanzees, and the first based on non-invasive sampling. In another four cases we were able to exclude all but two to five potential fathers, and in the remaining cases we were able to exclude all living males. For molecular ecologists SSR genotype databases offer important advantages over currently popular minisatellite DNA finger-printing: they can be analysed unequivocally using traditional population genetics techniques and they can be expanded through time and space by other researchers.

Mating in the nematode parasite Strongyloides ratti : proof of genetic exchange

Strongyloides, a parasitic nematode, has a complex life cycle that represents a transition between free-living and purely parasitic ways of life. By using minisatellite DNA fingerprinting, we have detected a large number of polymorphic loci in cloned lines of S. ratti. In controlled crosses between free-living adults of S. ratti, we show that genetic exchange, consistent with normal sexual reproduction, occurs. This is in contrast to earlier cytological studies which claimed that reproduction in this organism was by pseudogamy, and thus that inheritance was maternal only.