Incompatible Partners Research Articles

Genetic monogamy and mate choice in a pair-living primate

In pair-living mammals, genetic monogamy is extremely rare. One possible reason is that in socially monogamous animals, mate choice can be severely constrained, increasing the risk of inbreeding or pairing with an incompatible or low-quality partner. To escape these constraints, individuals might engage in extra-pair copulations. Alternatively, inbreeding can be avoided by dispersal. However, little is known about the interactions between mating system, mate choice, and dispersal in pair-living mammals. Here we genotyped 41 wild individuals from 14 groups of coppery titi monkeys (Plecturocebus cupreus) in Peruvian Amazon using 18 microsatellite loci. Parentage analyses of 18 young revealed no cases of extra-pair paternity, indicating that the study population is mostly genetically monogamous. We did not find evidence for relatedness- or heterozygosity-based mate choice. Despite the lack of evidence for active inbreeding avoidance via mate choice, mating partners were on average not related. We further found that dispersal was not sex-biased, with both sexes dispersing opportunistically over varying distances. Our findings suggest that even opportunistic dispersal, as long as it is not constrained, can generate sufficient genetic diversity to prevent inbreeding. This, in turn, can render active inbreeding avoidance via mate choice and extra-pair copulations less necessary, helping to maintain genetic monogamy.

Evolution of mating types in finite populations: The precarious advantage of being rare.

Sexually reproducing populations with self-incompatibility bear the cost of limiting potential mates to individuals of a different type. Rare mating types escape this cost since they are unlikely to encounter incompatible partners, leading to the deterministic prediction of continuous invasion by new mutants and an ever-increasing number of types. However, rare types are also at an increased risk of being lost by random drift. Calculating the number of mating types that a population can maintain requires consideration of both the deterministic advantages and the stochastic risks. By comparing the relative importance of selection and drift, we show that a population of size N can maintain a maximum of approximately N1/3 mating types for intermediate population sizes, whereas for large N, we derive a formal estimate. Although the number of mating types in a population is quite stable, the rare-type advantage promotes turnover of types. We derive explicit formulas for both the invasion and turnover probabilities in finite populations.

Collective sinking promotes selective cell pairing in planktonic pennate diatoms

Finding a partner in an inherently unsteady 3-dimensional system, such as the planktonic marine environment, is a difficult task for nonswimming organisms with poor control over their orientation. We experimentally investigate the process of cell pairing in pennate marine diatoms and present field evidence of its occurrence in the ocean. We describe the mechanism as a 3-step process in which pennate diatoms (i) vertically reorient while sinking from surface turbulent waters to a more stable environment (i.e., under the seasonal pycnocline), (ii) segregate from incompatible partners (e.g., dead or different sized cells), and (iii) pair with other partners as a result of the hydrodynamic instabilities generated by collective cell sinking. This is, eminently, a cell abundance-dependent process, therefore being more effective when population sinking is synchronized. We suggest that this selective process, enabling matching of size-compatible healthy partners, could be fundamental in understanding sexual reproduction in pennate diatoms.

Partner reactions and task set selection: Compatibility is more beneficial in the stronger task

Anticipated reactions performed by a partner affect action planning but it is unclear how they affect the selection of task sets. Therefore, four experiments varied partner reaction compatibility while subjects performed two tasks of asymmetric strength. Experiment 1 used an attentional selection paradigm that required reacting to endogenously or exogenously cued targets. The standard benefit for compatible partner reactions was only observed in the stronger task, whereas in the weaker task incompatible reactions reduced distractibility by irrelevant stimulus features. Experiment 2 replicated this interaction between task type and compatibility in a picture-word interference paradigm. It was hypothesized that the weaker task requires shielding the current goal from distraction by incompatible partner reactions, which leads to a generalized reduction of distractor interference. To test this hypothesis, Experiment 3 replicated Experiment 2 but forced subjects to attend to partner reactions. The interaction between task type and compatibility disappeared. To test whether task asymmetry is a necessary condition for this interaction, Experiment 4 used an attentional selection paradigm but reduced the difference in task strength. Compatibility benefits were found in both tasks. Taken together, the results suggest that while anticipated partner reactions can affect task set selection, their specific effects depend on selection demands.

Partner selection in disaster relief: Partnership formation in the presence of incompatible agencies

From terrorist attacks to tsunamis, natural and man-made disasters have had an increasingly pronounced impact on the world over the last century. While it is important to mitigate the effects of a disaster before it happens, it is also important to prepare an effective and flexible structure to help people, organizations, and governments develop to respond. Marked progress in the literature and in practice has helped humanitarian organizations become more interoperable, and also improved predictive capability for natural and man-made disasters. However, new problems and failures are brought to light with each new bombing, flood, hurricane, earthquake, or tsunami. This paper takes a previously understudied approach to post-disaster partnership selection using game theory. We analyze the dynamics of a sequential partnership selection game where there is a cost for working with an incompatible partner. Using a non-cooperative game structure, we identify some important dynamics that can be leveraged by agencies involved in disaster relief to help improve decision making and increase the impact of resource investments. For example, passing as much of the cost as possible to an incompatible partner, while also attempting to maintain the relationship, proved to be a poor approach to partnership. In this paper we look at how game theory could be used to help agencies make better decisions about whom to work with during the disaster response and recovery phases of a disaster.

University Students' knowledge, attitudes, and practices towards the National Premarital Screening Program of Saudi Arabia.

There is an elevated rate of hereditary hemoglobinopathies in Arab populations. To address this, the Saudi government has implemented a mandatory premarital screening (PMS) program. Nevertheless, reports have shown that 48% of genetically incompatible partners have decided to marry. To address this, more information is needed on people's beliefs on these issues. To investigate the knowledge, attitudes, and practices of Taif University students towards the national PMS program. Using a questionnaire, a cross-sectional study was conducted during April-May 2016 on a random sample of university students in Taif City. It was administered electronically and primarily distributed through social media. Most participants (97.4%) were aware that genes may transmit hereditary diseases and had heard about the PMS program. Most participants who partook in the PMS justified it based on preventing disease transmission to their offspring and ensuring their partner's health. A fair number (82.9%) were willing to change their decision to marry in the case of receiving incompatible results. Moreover, the majority of the participants (91.8%) demanded the implementation of a law that prohibits incompatible marriages. Most Taif University students have a generally positive attitude and good intended practices toward PMS. However, targeted educational programs about the importance of PMS are strongly recommended to eliminate all factors that may affect the success of the PMS program.

A polychromatic \u2018greenbeard\u2019 locus determines patterns of cooperation in a social amoeba

Cheaters disrupt cooperation by reaping the benefits without paying their fair share of associated costs. Cheater impact can be diminished if cooperators display a tag (‘greenbeard’) and recognise and preferentially direct cooperation towards other tag carriers. Despite its popular appeal, the feasibility of such greenbeards has been questioned because the complex patterns of partner-specific cooperative behaviours seen in nature require greenbeards to come in different colours. Here we show that a locus (‘Tgr’) of a social amoeba represents a polychromatic greenbeard. Patterns of natural Tgr locus sequence polymorphisms predict partner-specific patterns of cooperation by underlying variation in partner-specific protein–protein binding strength and recognition specificity. Finally, Tgr locus polymorphisms increase fitness because they help avoid potential costs of cooperating with incompatible partners. These results suggest that a polychromatic greenbeard can provide a key mechanism for the evolutionary maintenance of cooperation.

The assignment problem with nearly Monge arrays and incompatible partner indices

In this paper we study the d-dimensional assignment problem in which entries of the cost array satisfy the Monge property, except for ∞-entries, which may violate it. We assume that the ∞-entries are incurred by incompatible partner indices and their number is bounded by an upper bound λ for each index. We show that the problem can be solved in linear time for fixed d and λ, and it becomes strongly NP-hard if d or λ is part of the input.

Exploring the distance between ecofeminism and Women in Mining (WIM)

While there is existing work on the relationship between gender and mining in strands of environmental studies and resource studies, this paper moves away from generic feminist analyses of the environment and gender. Turning to ecofeminism, I argue that most debates that borrow from ecofeminism do not go beyond the maternalistic perspective that mining is anti-woman and thus anti-ecofeminist. This paper speaks to the gap in the literature by examining a specific group of gendered actors under the lens of ecofeminism, that is, women involved in the Women in Mining (WIM) movement. WIM represents a liberal feminism demand for equal opportunities for women in the otherwise heavily male-dominated and highly masculinised mining industry. However, in its current iteration WIM has not located its work within the discourse of ecofeminism, nor have its predominantly white, middleclass key stakeholders identified themselves as ecofeminists. As such, the complex intersectionalities of race, poverty, gender, age, class, and ideo-geographies are often neglected. In response, this paper queries, can ecofeminism and WIM enjoy a mutually beneficial relationship, and what might the impacts be for both sides of such a relationship? This paper begins with a summary of how the epistemological lens of ecofeminism can offer new understandings of and activism in the mining industry more generally. The next two sections present conceptual dialogues regarding how ecofeminism can challenge and reshape hegemonic practices and perspectives of WIM in its current iteration; and vice versa, how WIM can inform and enrich our understandings and applications of ecofeminism. In closing, the paper reflects on the apparent populist rhetoric of the two schools as incompatible partners.

Experimental Evolution of Species Recognition

Sex with another species can be disastrous, especially for organisms that mate only once, like yeast. Courtship signals, including pheromones, often differ between species and can provide a basis for distinguishing between reproductively compatible and incompatible partners. Remarkably, we show that the baker's yeast Saccharomyces cerevisiae does not reject mates engineered to produce pheromones from highly diverged species, including species that have been reproductively isolated for up to 100 million years. To determine whether effective discrimination against mates producing pheromones from other species is possible, we experimentally evolved pheromone receptors under conditions that imposed high fitness costs on mating with cells producing diverged pheromones. Evolved receptors allowed both efficient mating with cells producing the S. cerevisiae pheromone and near-perfect discrimination against cells producing diverged pheromones. Sequencing evolved receptors revealed that each contained multiple mutations that altered the amino acid sequence. By isolating individual mutations, we identified specific amino acid changes that dramatically improved discrimination. However, the improved discrimination conferred by these individual mutations came at the cost of reduced mating efficiency with cells producing the S. cerevisiae pheromone, resulting in low fitness. This tradeoff could be overcome by simultaneous introduction of separate mutations that improved mating efficiency alongside those that improved discrimination. Thus, if mutations occur sequentially, the shape of the fitness landscape may prevent evolution of the optimal phenotype--offering a possible explanation for the poor discrimination of receptors found in nature.

Divorce in the barn owl: securing a compatible or better mate entails the cost of re-pairing with a less ornamented female mate.

Two nonmutually exclusive hypotheses can explain why divorce is an adaptive strategy to improve reproductive success. Under the 'better option hypothesis', only one of the two partners initiates divorce to secure a higher-quality partner and increases reproductive success after divorce. Under the 'incompatibility hypothesis', partners are incompatible and hence they may both increase reproductive success after divorce. In a long-term study of the barn owl (Tyto alba), we address the question of whether one or the two partners derive fitness benefits by divorcing. Our results support the hypothesis that divorce is adaptive: after a poor reproductive season, at least one of the two divorcees increase breeding success up to the level of faithful pairs. By breeding more often together, faithful pairs improve coordination and thereby gain in their efficiency to produce successful fledglings. Males would divorce to obtain a compatible mate rather than a mate of higher quality: a heritable melanin-based signal of female quality did not predict divorce (indicating that female absolute quality may not be the cause of divorce), but the new mate of divorced males was less melanic than their previous mate. This suggests that, at least for males, a cost of divorce may be to secure a lower-quality but compatible mate. The better option hypothesis could not be formally rejected, as only one of the two divorcing partners commonly succeeded in obtaining a higher reproductive success after divorce. In conclusion, incompatible partners divorce to restore reproductive success, and by breeding more often together, faithful partners improve coordination.

Incompatibility Between X Chromosome Factor and Pericentric Heterochromatic Region Causes Lethality in Hybrids Between Drosophila melanogaster and Its Sibling Species

The Dobzhansky-Muller model posits that postzygotic reproductive isolation results from the evolution of incompatible epistatic interactions between species: alleles that function in the genetic background of one species can cause sterility or lethality in the genetic background of another species. Progress in identifying and characterizing factors involved in postzygotic isolation in Drosophila has remained slow, mainly because Drosophila melanogaster, with all of its genetic tools, forms dead or sterile hybrids when crossed to its sister species, D. simulans, D. sechellia, and D. mauritiana. To circumvent this problem, we used chromosome deletions and duplications from D. melanogaster to map two hybrid incompatibility loci in F(1) hybrids with its sister species. We mapped a recessive factor to the pericentromeric heterochromatin of the X chromosome in D. simulans and D. mauritiana, which we call heterochromatin hybrid lethal (hhl), which causes lethality in F(1) hybrid females with D. melanogaster. As F(1) hybrid males hemizygous for a D. mauritiana (or D. simulans) X chromosome are viable, the lethality of deficiency hybrid females implies that a dominant incompatible partner locus exists on the D. melanogaster X. Using small segments of the D. melanogaster X chromosome duplicated onto the Y chromosome, we mapped a dominant factor that causes hybrid lethality to a small 24-gene region of the D. melanogaster X. We provide evidence suggesting that it interacts with hhl(mau). The location of hhl is consistent with the emerging theme that hybrid incompatibilities in Drosophila involve heterochromatic regions and factors that interact with the heterochromatin.

Inequalities of love: college-educated black women and the barriers to romance and family

Inequalities of Love uses the personal narratives of college-educated black women to describe the difficulties they face when trying to date, marry, and have children. While conventional wisdom suggests that all women, regardless of race, must sacrifice romance and family for advanced educations and professional careers, Averil Y. Clarke's research reveals that educated black women's disadvantages in romance and starting a family are consequences of a system of racial inequality and discrimination. The author analyzes the accounts of black women who repeatedly return to incompatible partners as they lose hope of finding Mr. Right and reject unwed parenting because it seems to affirm a negative stereotype of black women's sexuality that is inconsistent with their personal and professional identities. She uses national survey data to compare college-educated black women's experiences of romance, reproduction, and family to those of less-educated black women and those of white and Hispanic women with degrees. She reports that degreed black women's lives include less marriage and sex, and more unwanted pregnancy, abortion, and unwed childbearing than college-educated white and Hispanic women. Black women's romantic limitations matter because they constitute deprivation and constraint in romance and because they illuminate important links between race, class, and gender inequality in the United States. Clarke's discussion of the inequities that black women experience in romance highlights the connections between individuals' sexual and reproductive decisions, their performance of professional or elite class identities, and the avoidance of racial stigma.

Incompatible Partners: The Role of Identity and Self-Image in the Sino-U.S. Relationship

This article examines identity as an underexplored factor complicating U.S.-China relations and concludes that the identity variable contributes to mutual suspicion and frustrates efforts in conflict resolution.

Incompatible partners? Urban poor communities and river systems in Bangkok, Thailand

Asian cities are confronted with a range of environmental challenges with few success stories. State-driven and top-down solutions have been only partially successful, while communities struggle with developing and implementing alternative strategies that are affordable and result in safer and more liveable environments. River systems are increasingly at the centre of many of these struggles. In part this has been because current and past approaches, which often involve cleaning/beautifying waterways and 'relocating' the urban poor, have proven prohibitively expensive and have led to conflict with affected communities for which few alternative shelter and livelihood alternatives exist. Yet there are innovative approaches led by communities and NGOs, sometimes in partnership with governments but at other times in opposition to official projects. This paper, based on fieldwork in Bangkok, examines such 'grey areas' of planning, in which community-based solutions and partnerships that deal with polluted environments and seek to avoid eviction have been developed in partnership with aid agencies and governments. I examine how successful these community/partner responses have been; how they are viewed by governments, donors and communities; and to what extent they can be considered as viable pathways to cleaner urban waterways and sustainable cities.

Maternal adjustment of parental effort in relation to mate compatibility affects offspring development

Theory predicts that parents should adjust reproductive investment in a current breeding attempt by considering the relative fitness benefits of current and future reproductive attempts. Empirical tests, however, have proved problematic because of the difficulties in isolating variables that yield clear and predictable fitness returns to individuals and because partner compensation in socially monogamous species is likely to confound individual investment strategies. We test the effect of parental investment by males and females in the color polymorphic Gouldian finch (Erythrura gouldiae), a species with mutual mate choice and high fitness costs when breeding with incompatible partners. Using a within-individual experimental design, in which both males and females were forced to breed with mates of the same (matched) and different (mixed) color morph, we show that females, but not males, increased their provisioning effort when breeding with compatible mates. By crossfostering offspring within and between matched and mixed pairs, we also found that foster offspring reared by matched pairs, with increased female provisioning, were healthier, grew and developed faster, and fledged earlier than offspring reared by mixed pairs. Furthermore, due to the experimental design, these effects were directly mediated by differential investment by females and not by male compensation. Thus, our results provide support for maternal (but not paternal) effects in response to mate quality. Key words: differential allocation, genetic incompatibility, maternal investment, parental care. [Behav Ecol]

Genetic Incompatibility Drives Sex Allocation and Maternal Investment in a Polymorphic Finch

Genetic compatibility may drive individual mate choice decisions because of predictable fitness effects associated with breeding with incompatible partners. In Gouldian finches (Erythrura gouldiae), females paired with genetically incompatible males of alternative color morphs overproduce sons, presumably to reduce investment in inviable daughters. We also observed a reduced overall investment in clutch size, egg size, and care to offspring resulting from incompatible matings. Within-female experimental pairings demonstrate that female birds have the ability to adaptively adjust the sex of their eggs and allocate resources on the basis of partner quality. Female Gouldian finches thus make cumulative strategic allocation decisions to minimize the costs of poor-quality pairings when faced with a genetically incompatible partner.

Physiological and biochemical changes at the rootstock-scion interface in graft combinations between Cucurbita rootstocks and a melon scion

SummarySuccess in grafting depends on the identification of a compatible rootstock (RS) that promotes rapid formation of vascular connections between the RS and the scion, and rapid resumption of root and shoot growth. In this study, we used compatible and incompatible Cucurbita rootstocks, with a melon (Cucumis melo L. ‘Arava’) scion, to identify physiological and biochemical factors in the scion-RS interface that could be associated with graft compatibility. Anatomical characterisation of the grafting interface showed that the regeneration and differentiation of vascular elements was similar, at first, in both compatible and incompatible grafted seedlings although, in the latter, a protective layer was formed, but did not interfere with communication between the RS and the scion. Water uptake and sugar distribution between the plant canopy and the roots, measured 14 d after grafting (DAG) were not correlated with compatibility or incompatibility. At 24 DAG, both water uptake and root sugar concentrations decreased significantly in the incompatible RS, reflecting deterioration of the RS. At 24 DAG, part of the RS collapsed, but only in incompatible grafted seedlings. Histochemical staining revealed that superoxide, H2O2, peroxidase (POX) activity, and lignin deposits at the scion-rootstock interface were similar in both compatible and incompatible grafting combinations at 14 DAG; but, at 24 DAG, H2O2 and superoxide levels were higher in the incompatible grafted transplants. In addition, cell-wall POX and superoxide dismutase (SOD) activities were lower in the incompatible RS-scion interface at 14 and 24 DAG. These results suggest that a physical barrier is unlikely to be formed between the incompatible partners early after grafting, but that lower anti-oxidant enzyme activities and higher levels of reactive oxygen species (ROS) in the incompatible RS-scion interface may be responsible for degradation of the grafting zone.

Differential induction of phenylalanine ammonia-lyase gene expression in response to in vitro callus unions of Prunus spp.

Phenylalanine ammonia-lyase (PAL) is a key enzyme in the synthesis of phenolic compounds, which play a prominent role in graft union formation, including the marked effects of their accumulation in incompatibility response. The purpose of this study was to assess changes in the abundance of PAL mRNA during graft union development. Partial cDNA clones encoding the enzyme were isolated from in vitro callus tissue in the apricot (Prunus armeniaca L.) cultivar Moniqui and the plum rootstock Marianna 2624 (Prunus munsoniana x Prunus cerasifera). The deduced partial amino acid sequence showed high homology with PAL genes from other plant species. We monitored PAL expression 5, 10, 15 and 20 days after the establishment of in vitro callus unions. The levels of PAL mRNA increased 5 days after grafting in both compatible and incompatible unions. Nevertheless, significant differences were observed at the transcript level through both types of combinations from the second week. The results showed a higher level of PAL transcription in graft unions of incompatible partners, where a lack of adaptation between stock and scion takes place. The level of scion-stock compatibility was related to the PAL expression pattern. In addition, cell walls of the callus cells were not stained by phloroglucinol-HCl, indicating that the increased PAL expression did not result in the formation of lignin. However, staining with Naturstoff reagent A confirmed the highest accumulation of soluble and wall-bound phenolic compounds at the graft interface of incompatible unions.

Production and Evaluation of Somatic Hybrids Derived from Monoploid Potato

Biotechnological approaches to hasten hybrid plant breeding are available, including anther culture to halve the genome and protoplast fusion to create hybrids between incompatible partners. We applied these techniques to potato to evaluate their potential for breeding a highly heterozygous, cross-pollinating species. Four families of monoploids (2n=1x=12), developed from diploid hybrids with various genomic constitutions favoringSolarium phureja, an ancestral cultivated potato subsequently selected for tuberization under long photoperiod, were used in electrofusion experiments to create intermonoploid somatic hybrids. The “monoploid sieve” results in the survival of only those gametes free of lethal and deleterious genes, but it generates sterile sporophytes, necessitating protoplast fusion for developing hybrids from differentially derived monoploids. From six intermonoploid electrofusion combinations, 178 plants, including both somaclones and somatic hybrids confirmed by microsatellite analysis, were regenerated over six to nine months. Fusion conditions of 8 V for 45 sec with two pulses and 12 V for 30 sec and one pulse were optimum. Ploidy of the fusion products as determined by flow cytometry ranged from 2x to 8x with only somaclones at the 2x level and both 4x and 6x somatic hybrids. Field evaluations over three years revealed that intermonoploid somatic hybrids were inferior toSolarium tuberosum cultivars. Dihaploids derived by anther culture of a tetraploid intermonoploid somatic hybrid were reduced in vigor with the increase in homozygosity, while 2x X 2x sexually derived populations were similar in yield to the somatic hybrids. The biotechnological breeding scheme to reduce generation time will require selection for horticultural traits during inbreeding in order to produce potatoes more similar to cultivars. The elimination of epistatic and/or intra-allelic interactions through reduc-tion of ploidy may underlie the poor performance of monoploids, doubled monoploids and dihaploids as well as most somatic hybrids compared to conventionally bred potato germplasm.