Abo blood groups and completed reproductive performance of rural Haryanavi couples: analysing measures of selection intensities

The possible differential effects of ABO blood group materno-paternal (fetal) incompatibility on completed reproductive performance were investigated on a sample of 100 couples (100 fathers and 100 mothers) from three villages in the Jind district of Haryana state, India. The average number of live births per mating couple was slightly higher for the incompatible matings (5.32) than the compatible ones (5.05). This advantage was offset by higher postnatal mortality in the former. Consequently, the average number of living children in the compatible matings (4.64) was higher than in the incompatible ones (4.18). With reference to individual ABO matings, the index of relative fertility (Irf) was the highest in A x AB followed by B x A type of incompatible matings. No decrease in live births in O x A and O x B incompatible matings was observed compared with their reciprocal compatible ones, i.e. A x O and B x O matings, as has been hypothesized in previous studies. The total pregnancy wastage was substantially higher in ABO-incompatible matings (24.59%) than compatible matings (8.45%). About 71% of the postnatal deaths took place within one year of the birth in the case of incompatible matings compared with 50% in the case of compatible matings. The study supports the hypothesis that selection is operative at the ABO locus as revealed by the measures of selection intensity. The loss of fitness in the present sample was associated with differential mortality. There were no differences in the proportions of average number of male live births in the compatible (0.55) and incompatible matings (0.58). However, in the individual mating types, there was some evidence of higher or lower proportions of male live births.     

ABO blood groups and fertility in an Indian population

A total of 589 compatible mating couples could be investigated against 432 incompatible mating couples in order to determine the selective mechanism operating on ABO blood groups. There appears to be no striking difference in the proportion of childless couples between the two groups. The mean number of living children presents a significant difference. There is 21% deficiency of 'A' children in the two groups. Similarly, there is 16% deficiency of 'B' children in the two groups. It appears that there is 31.9% fetal wastage in incompatible matings as compared with 17.15% in compatible matings.     

木耳和毛木耳的极性研究*

从木耳(Auricularia auricula)和毛木耳(A.polytricha)的同一子实体弹射、分离30个单孢子并发育成单核菌丝体,各自分成3组,以10×10方式进行单核体两两配对。取两配对单核体交结处菌丝体块到新的平板上继续发育并插入无菌的盖玻片让其菌丝爬上。后利用双苯并咪唑(Hoechst 33258)染色,在萤光显微镜下逐块检查配对后菌丝体细胞中核的数目。如果出现双核,再加以检查锁状联合以验证,则为配对亲和。不亲和者仍为单核。根据配对行为进行不亲和因子分配决定其交配型。检测结果表明,木耳和毛木耳担孢子的性别是由一对遗传因子A.a所控制。属典型性二极性(bipolar)异宗结合。     

木耳和毛木耳的极性研究

从木耳(Auricularia auricula)和毛木耳(A.polytricha)的同一子实体弹射、分离30个单孢子并发育成单核菌丝体,各自分成3组,以10×10方式进行单核体两两配对。取两配对单核体交结处菌丝体块到新的平板上继续发育并插入无菌的盖玻片让其菌丝爬上。后利用双苯并咪唑(Hoechst 33258)染色,在萤光显微镜下逐块检查配对后菌丝体细胞中核的数目。如果出现双核,再加以检查锁状联合以验证,则为配对亲和。不亲和者仍为单核。根据配对行为进行不亲和因子分配决定其交配型。检测结果表明,木耳和毛木耳担孢子的性别是由一对遗传因子A.a所控制。属典型性二极性(bipolar)异宗结合。     

Multiple Versions of the a Mating Type Locus of Coprinus Cinereus Are Generated by Three Paralogous Pairs of Multiallelic Homeobox Genes

The A mating type locus of Coprinus cinereus determines mating compatibility by regulating essential steps in sexual development. Each A locus contains several genes separated into two functionally independent complexes termed Aα and Aβ, and the multiple alleles of these genes generate an estimated 160 A mating specificities. The genes encode two classes of homeodomain-containing proteins designated HD1 and HD2. In this report we describe two newly cloned loci, A2 and A5, and compare them with A42, A43 and A6 that we have described previously. An Aβ-null locus, retaining just a single active HD1 gene from the α-complex, was generated by mutation. Using this as a transformation host, gene combinations that promote A-regulated development were identified. We demonstrate that each A locus contains members of three paralogous pairs of HD1 and HD2 genes. Different allelic versions of gene pairs are compatible but paralogous genes are incompatible. The genes present in four uncloned A loci were deduced using Southern analyses and transformations with available cloned genes. The combined analysis of nine A factors identifies sufficient A gene alleles to generate at least 72 A mating specificities.     

Many compatible Wolbachia strains coexist within natural populations of Culex pipiens mosquito

Maternally inherited Wolbachia often manipulate the reproduction of arthropods to promote their transmission. In most species, Wolbachia exert a form of conditional sterility termed cytoplasmic incompatibility (CI), characterized by the death of embryos produced by the mating between individuals with incompatible Wolbachia infections. From a theoretical perspective, no stable coexistence of incompatible Wolbachia infections is expected within host populations and CI should induce the invasion of one strain or of a set of compatible strains. In this study, we investigated this prediction on CI dynamics in natural populations of the common house mosquito Culex pipiens. We surveyed the Wolbachia diversity and the expression of CI in breeding sites of the south of France between 1990 and 2005. We found that geographically close C. pipiens populations harbor considerable Wolbachia diversity, which is stably maintained over 15 years. We also observed a very low frequency of infertile clutches within each sampled site. Meanwhile, mating choice experiments conducted in laboratory conditions showed that assortative mating does not occur. Overall, this suggests that a large set of compatible Wolbachia strains are always locally dominant within mosquito populations thus, fitting with the theoretical expectations on CI dynamics.     

Functional gametophytic self-incompatibility in a peripheral population of Solanum peruvianum (Solanaceae)

The transition from self-incompatibility to self-compatibility is a common transition in angiosperms often reported in populations at the edge of species range limits. Geographically distinct populations of wild tomato species (Solanum section Lycopersicon (Solanaceae)) have been described as polymorphic for mating system with both self-incompatible and self-compatible populations. Using controlled pollinations and sequencing of the S-RNase mating system gene, we test the compatibility status of a population of S. peruvianum located near its southern range limit. Pollinations among plants of known genotypes revealed strong self-incompatibility; fruit set following compatible pollinations was significantly higher than following incompatible pollinations for all tested individuals. Sequencing of the S-RNase gene in parents and progeny arrays was also as predicted under self-incompatibility. Molecular variation at the S-RNase locus revealed a diverse set of alleles, and heterozygosity in over 500 genotyped individuals. We used controlled crosses to test the specificity of sequences recovered in this study; in all cases, results were consistent with a unique allelic specificity for each tested sequence, including two alleles sharing 92% amino-acid similarity. Site-specific patterns of selection at the S-RNase gene indicate positive selection in regions of the gene associated with allelic specificity determination and purifying selection in previously characterized conserved regions. Further, there is broad convergence between the present and previous studies in specific amino-acid positions inferred to be evolving under positive selection.     

A cytochrome P450 gene is differentially expressed in compatible and incompatible interactions between pepper (Capsicum annuum) and the anthracnose fungus, Colletotrichum gloeosporioides

The anthracnose fungus, Colletotrichum gloeosporioides, was previously shown to have an incompatible interaction with ripe-red fruit of pepper (Capsicum annuum). However, the fungus had a compatible interaction with unripe-mature-green fruit. Using mRNA differential display, we isolated and characterized a PepCYP gene expressed in the incompatible interaction. The PepCYP gene encodes a protein homologous to cytochrome P450 proteins containing a heme-binding domain. The expression level of PepCYP is higher in the incompatible interaction than in the compatible interaction, and then remains elevated in the incompatible interaction. In the compatible interaction, the expression of PepCYP is transient. The induction of PepCYP gene is up-regulated by wounding or jasmonic acid treatment during ripening. Analysis of PepCYP expression by in situ hybridization shows that the accumulation of PepCYP mRNA is localized in the epidermal cell layers, but not in the cortical cell layers. An examination of transverse sections of the fruits inoculated with the fungus shows that the fungus invades and colonizes the epidermal cell layers of the unripe fruit at 24 and 72 h after inoculation, respectively, but not those of the ripe fruit. These results suggest that the PepCYP gene product plays a role in the defense mechanism when the fungus invades and colonizes the epidermal cells of fruits in the incompatible interaction during the early fungal infection process.     

Biphasic gene expression changes elicited by Phakopsora pachyrhizi in soybean correlate with fungal penetration and haustoria formation

Inoculation of soybean (Glycine max) plants with Phakopsora pachyrhizi, the causal organism of Asian soybean rust, elicits a biphasic response characterized by a burst of differential gene expression in the first 12 h. A quiescent period occurs from 24 to 48 h after inoculation, in which P. pachyrhizi continues to develop but does not elicit strong host responses, followed by a second phase of intense gene expression. To correlate soybean responses with P. pachyrhizi growth and development, we inoculated the soybean cultivar Ankur (accession PI462312), which carries the Rpp3 resistance gene, with avirulent and virulent isolates of P. pachyrhizi. The avirulent isolate Hawaii 94-1 elicits hypersensitive cell death that limits fungal growth on Ankur and results in an incompatible response, while the virulent isolate Taiwan 80-2 grows extensively, sporulates profusely, and produces a compatible reaction. Inoculated leaves were collected over a 288-h time course for microarray analysis of soybean gene expression and microscopic analysis of P. pachyrhizi growth and development. The first burst in gene expression correlated with appressorium formation and penetration of epidermal cells, while the second burst of gene expression changes followed the onset of haustoria formation in both compatible and incompatible interactions. The proliferation of haustoria coincided with the inhibition of P. pachyrhizi growth in the incompatible interaction or the beginning of accelerated growth in the compatible interaction. The temporal relationships between P. pachyrhizi growth and host responses provide an important context in which to view interacting gene networks that mediate the outcomes of their interactions.     

Vegetative Incompatibility and the Mating-Type Locus in the Cellular Slime Mold DICTYOSTELIUM DISCOIDEUM

The genetic basis of vegetative incompatibility in the cellular slime mold, Dictyostelium discoideum, is elucidated. Vegetatively compatible haploid strains from parasexual diploids at a frequency of between 10^-6 and 10^-5, whereas "escaped" diploids are formed between vegetatively incompatible strains at a frequency of ~10^-8. There is probably only a single vegetative incompatibility site, which appears to be located at, or closely linked to, the mating-type locus. The nature of the vegetative incompatibility is deduced from parasexual diploid formation between wild isolates and tester strains of each mating type, examination of the frequency of formation of "escaped" diploids formed between vegetatively incompatible strains, and examination of the mating type and vegetative incompatibility of haploid segregants obtained from "escaped" diploids.     

iTRAQ‐based proteomics of sunflower cultivars differing in resistance to parasitic weed Orobanche cumana

Orobanche cumana is an obligate root parasite causing severe damage to many economically important crops, including sunflowers worldwide. For efficient control measures, it is necessary to understand the resistant mechanism during interaction at molecular level. The present study emphasizes on comparative proteomics to investigate the mechanistic basis of compatible and incompatible interaction of O. cumana with resistant (JY207) and susceptible (TK0409) sunflowers. More than 3500 proteins were identified from two cultivars by iTRAQ analysis. Identified proteins associated with general functions, posttranslational modification, energy production and conversion, carbohydrate transport and metabolism, and signal transduction mechanisms were the most represented category of induced proteins in both cultivars. The resistant interaction was characterized by alteration of defense‐related proteins involved in recognition of parasites, accumulation of pathogenesis‐related proteins, biosynthesis of lignin, and detoxification of toxic metabolites in JY207 after inoculation. The susceptible interaction was characterized by decreased abundance of proteins involved in biosynthesis and signaling of plant growth regulators including auxin, gibberellin, brassinosteroid, and ethylene in TK0409 after inoculation. The present study provides comprehensive details of proteins and differential modulation of pathways regulated under compatible and incompatible interaction, allowing the identification of important molecular components for development of sustainable resistance against this parasite.     

Genetic quality and sexual selection: an integrated framework for good genes and compatible genes

Why are females so choosy when it comes to mating? This question has puzzled and marveled evolutionary and behavioral ecologists for decades. In mating systems in which males provide direct benefits to the female or her offspring, such as food or shelter, the answer seems straightforward — females should prefer to mate with males that are able to provide more resources. The answer is less clear in other mating systems in which males provide no resources (other than sperm) to females. Theoretical models that account for the evolution of mate choice in such nonresource-based mating systems require that females obtain a genetic benefit through increased offspring fitness from their choice. Empirical studies of nonresource-based mating systems that are characterized by strong female choice for males with elaborate sexual traits (like the large tail of peacocks) suggest that additive genetic benefits can explain only a small percentage of the variation in fitness. Other research on genetic benefits has examined nonadditive effects as another source of genetic variation in fitness and a potential benefit to female mate choice. In this paper, we review the sexual selection literature on genetic quality to address five objectives. First, we attempt to provide an integrated framework for discussing genetic quality. We propose that the term ‘good gene’ be used exclusively to refer to additive genetic variation in fitness, ‘compatible gene’ be used to refer to nonadditive genetic variation in fitness, and ‘genetic quality’ be defined as the sum of the two effects. Second, we review empirical approaches used to calculate the effect size of genetic quality and discuss these approaches in the context of measuring benefits from good genes, compatible genes and both types of genes. Third, we discuss biological mechanisms for acquiring and promoting offspring genetic quality and categorize these into three stages during breeding: (i) precopulatory (mate choice); (ii) postcopulatory, prefertilization (sperm utilization); and (iii) postcopulatory, postfertilization (differential investment). Fourth, we present a verbal model of the effect of good genes sexual selection and compatible genes sexual selection on population genetic variation in fitness, and discuss the potential trade-offs that might exist between mate choice for good genes and mate choice for compatible genes. Fifth, we discuss some future directions for research on genetic quality and sexual selection.     

Cloning,sequence and characterization of a sunflower (Helianthus annuus L.) pathogen-induced gene showing sequence homology with auxin-induced genes from plants

The establishment of a plant-pathogen interaction involves changes in gene expressions in both organisms. To isolate Helianthus annuus genes whose expression is induced during processes of resistance to Plasmopara halstedii, a comparison of the expression pattern of healthy sunflowers was made with sunflowers infected with 2 races of P. halstedii, either virulent or avirulent, using differential display of mRNA. A full-length cDNA, HaAC1, representing a sunflower gene whose expression is enhanced during early stages of the incompatible interaction, was isolated. Different timing of RNA accumulation is observed between compatible and incompatible combinations. Sequence analysis and database search revealed significant homology with auxin-induced genes from plants. The expression of this gene, is also induced after treatment with 2,4-dichlorophenoxyacetic acid (2,4-D), salicylic acid (SA) and wounding.     

Isolation of pheromone precursor genes of Magnaporthe grisea.

In heterothallic ascomycetes one mating partner serves as the source of female tissue and is fertilized with spermatia from a partner of the opposite mating type. The role of pheromone signaling in mating is thought to involve recognition of cells of the opposite mating type. We have isolated two putative pheromone precursor genes of Magnaporthe grisea. The genes are present in both mating types of the fungus but they are expressed in a mating type-specific manner. The MF1-1 gene, expressed in Mat1-1 strains, is predicted to encode a 26-amino-acid polypeptide that is processed to produce a lipopeptide pheromone. The MF2-1 gene, expressed in Mat1-2 strains, is predicted to encode a precursor polypeptide that is processed by a Kex2-like protease to yield a pheromone with striking similarity to the predicted pheromone sequence of a close relative, Cryphonectria parasitica. Expression of the M. grisea putative pheromone precursor genes was observed under defined nutritional conditions and in field isolates. This suggests that the requirement for complex media for mating and the poor fertility of field isolates may not be due to limitation of pheromone precursor gene expression. Detection of putative pheromone precursor gene mRNA in conidia suggests that pheromones may be important for the fertility of conidia acting as spermatia.     

Selection for Increased Mutation Rates with Fertility Differences between Matings

Previous studies of mutation modification have considered models in which selection is a result of viability differences that are sex symmetric. The results of a numerical study of a model in which selection is a result of fertility differences between mated pairs demonstrate that the type of selection to which a population is subject can have a significant impact on the evolution of various parameters of the genetic system. When the fertility of matings between individuals with different genotypes exceeds the fertility of at least some of the matings between individuals with the same genotype, selection may favor increased rates of mutation, in contrast to the results from all existing constant viability models with random mating and infinite population size. Increased mutation rates are most frequently favored when forward and back mutation occur at approximately equal rates and when the modifying locus is loosely linked to the selected locus. We present one example in which selection favors increased rates of mutation even though the selection scheme is reducible to one of differential viability between the sexes.