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At least 1,189 records · Page 66Linked to original sources
PubMed1997

Insulin VNTR allele-specific effect in type 1 diabetes depends on identity of untransmitted paternal allele. The IMDIAB Group.

The IDDM2 type 1 diabetes susceptibility locus was mapped to and identified as allelic variation at the insulin gene (INS) VNTR regulatory polymorphism. In Caucasians, INS VNTR alleles divide into two discrete size classes. Class I alleles (26 to 63 repeats) predispose in a recessive way to type 1 diabetes, while class III alleles (140 to more than 200 repeats) are dominantly protective. The protective effect may be explained by higher levels of class III VNTR-associated INS mRNA in thymus such that elevated levels of preproinsulin protein enhance immune tolerance to preproinsulin, a key autoantigen in type 1 diabetes pathogenesis. The mode of action of IDDM2 is complicated, however, by parent-of-origin effects and possible allelic heterogeneity within the two defined allele classes. We have now analysed transmission of specific VNTR alleles in 1,316 families and demonstrate that a particular class I allele does not predispose to disease when paternally inherited, suggestive of polymorphic imprinting. But this paternal effect is observed only when the father's untransmitted allele is a class III. This allelic interaction is reminiscent of epigenetic phenomena observed in plants (for example, paramutation; ref. 17) and in yeast (for example, trans-inactivation; ref. 18). If untransmitted chromosomes can have functional effects on the biological properties of transmitted chromosomes, the implications for human genetics and disease are potentially considerable.

Alleles↗
PubMed2001

Paternal transmission of the very common class I INS VNTR alleles predisposes to childhood obesity.

To identify some of the genetic factors that contribute to obesity in children of Central European and North African descent, we studied the parental transmission of alleles at the insulin locus to offspring with early-onset obesity. A variable nucleotide tandem repeat (VNTR) polymorphism upstream of the insulin gene (INS) is associated with variations in the expression of INS and the nearby gene encoding insulin-like growth factor 2 (IGF2). We found an excess of paternal transmission of class I VNTR alleles to obese children: children who inherited a class I allele from their father (but not those inheriting it from their mother) had a relative risk of early-onset obesity of 1.8. Due to the frequency of class I alleles in this population, this risk concerns 65-70% of all infants. These results suggest that increased in utero expression of paternal INS or IGF2 due to the class I INS VNTR allele may predispose offspring to postnatal fat deposition.

Adolescent↗
PubMed2005

Paternal contribution: new insights and future challenges.

It has been widely held that all that fathers essentially contribute to the next generation is half their genome. However, recent progress towards understanding biological processes such as sperm maturation and fertilization now indicates that the paternal contribution has been underestimated. To tackle some of the misconceptions surrounding the paternal contribution, the factors that are actually delivered by the sperm at fertilization and their potential developmental functions will be discussed using data from humans and animal models. Although still in their infancy, the practical applications of using sperm RNAs have already emerged in reproductive medicine as markers that are indicative of successful vasectomy. They are also beginning to appear in the forensic sciences and, within the next decade, might appear in the environmental sciences.

Animals↗
PubMed2001

Transplantation of a fetus with paternal Thy-1(+)CD34(+)cells for chronic granulomatous disease.

A fetus diagnosed with X-linked chronic granulomatous disease was transplanted with Thy-1(+)CD34(+) cells of paternal origin. The transplant was performed at 14 weeks gestation by ultrasound guided injection into the peritoneal cavity. The fetus was delivered at 38 weeks gestation after an otherwise uneventful pregnancy. Umbilical cord blood was collected and used to determine the level of peripheral blood chimerism as well as levels of functional engrafted cells. Flow cytometry was used to detect donor leukocytes identified as HLA-A2(-)B7(+) cells, whereas recipient cells were identified as HLA-A2(+)B7(-) cells. No evidence of donor cell engraftment above a level of 0.01% was found. PCR was used to detect HLA-DRB1*15(+) donor cells among the recipient's HLA-DRB1*15(-) cells, but no engraftment was seen with a sensitivity of 1:1000. The presence of functional, donor-derived neutrophils was assessed by flow cytometry using two different fluorescent dyes that measure reactive oxygen species generated by the phagocyte NADPH oxidase. No evidence of paternal-derived functional neutrophils above a level of 0.15% was observed. Peripheral blood and bone marrow samples were collected at 6 months of age. Neither sample showed engraftment by HLA typing using both flow cytometry and PCR. Functional phagocytes were also not observed. Furthermore, no indication of immunological tolerance specific for the donor cells was indicated by a mixed lymphocyte reaction assay performed at 6 months of age. While there appears to be no engraftment of the donor stem cells, the transplant caused no harm to the fetus and the child was healthy at 6 months of age. Analyses of fetal tissues, obtained from elective abortions, revealed that CD3(+) T cells and CD56(+)CD3(-) NK cells are present in the liver at 8 weeks gestation and in the blood by 9 weeks gestation. The presence of these lymphocytes may contribute to the lack of donor cell engraftment in the human fetus.

Adult↗
PubMed2001

Superior survival of blood and marrow stem cell recipients given maternal grafts over recipients given paternal grafts.

During the reproductive period, mothers and offspring exchange hematopoietic cells and develop a form of immunological tolerance bidirectionally. To examine whether previous experience of such communication has any remote effect when maternal hematopoietic cells are later transplanted to the children, we retrospectively compared the outcomes of blood and marrow stem cell transplantation from maternal donors (n = 46) to those from paternal donors (n = 50) by using the database of the Japanese nationwide surveys for adult hematopoietic cell transplants between 1990 and 1998. At 5 years, recipients of maternal hematopoietic cells had a significantly higher overall survival than patients receiving paternal grafts (60% vs 32%, P = 0.006). Although no significant difference was observed in the occurrence of severe acute GVHD (grade > or =III) and the relapse of malignant diseases between two groups, the probability of non-relapse treatment-related mortality was significantly lower after maternal donor transplants. Furthermore, multivariate analysis revealed that parental donor type was the only factor significantly associated with overall survival. In conclusion, our analysis indicates superior survival of maternally donated recipients in hematopoietic stem-cell transplantations from biological parents. This finding has important implications in the selection of alternative familial donors, and warrants further prospective analysis of parental donor transplantations.

Adolescent↗
PubMed2000

A reinvestigation of non-disjunction resulting in 47, XXY males of paternal origin.

We have used polymorphisms within the Xp/Yp pseudoautosomal region (PAR 1) to determine the frequency and location of recombination in 80 paternally derived 47, XXY males. Of 64 informative results, there were 10 single cross-overs, one double cross-over and 53 without a cross-over. Therefore 2/3 of 47, XXY males of paternal origin result from meiosis in which the X and Y chromosomes fail to recombine. This failure was not associated with the presence of an increase in recombination in the smaller Xq/Yq pseudoautosomal region (PAR 2) or with the presence of microdeletions within PAR 1.

Adult↗
PubMed2005

Paternal deletion of the GNAS imprinted locus (including Gnasxl) in two girls presenting with severe pre- and post-natal growth retardation and intractable feeding difficulties.

Deletions of the long arm of chromosome 20 are rare. Here, we report on two girls with a very small interstitial deletion of the long arm of chromosome 20 presenting with severe pre- and post-natal growth retardation, intractable feeding difficulties, abnormal subcutaneous adipose tissue, similar facial dysmorphism, psychomotor retardation and hypotonia. Standard cytogenetic studies were normal, but high-resolution chromosomes analysis showed the presence of a chromosome (20)(q13.2-q13.3) interstitial deletion. Karyotypes of both parents were normal. Molecular studies using FISH and microsatellite polymorphic markers showed that the deletion was of paternal origin and was approximatively 4.5 Mb in size. A review of other reported patients with similar deletions of the long arm of chromosome 20 shows that the observed phenotype might be explained in the light of the GNAS imprinted locus in particular by the absence of the Gnasxl paternally imprinted gene and the TFA2PC gene in the deleted genetic interval.

Adult↗
PubMed2005

Patterns of pollen dispersal in a small population of Pinus sylvestris L. revealed by total-exclusion paternity analysis.

Patterns of pollen dispersal were investigated in a small, isolated, relict population of Pinus sylvestris L., consisting of 36 trees. A total-exclusion battery comprising four chloroplast and two nuclear microsatellites (theoretical paternity exclusion probability EP=0.996) was used to assign paternity to 813 seeds, collected from 34 trees in the stand. Long-distance pollen immigration accounted for 4.3% of observed matings. Self-fertilization rate was very high (0.25), compared with typical values in more widespread populations of the species. The average effective pollen dispersal distance within the stand was 48 m (or 83 m excluding selfs). Half of effective pollen was dispersed within 11 m, and 7% beyond 200 m. A strong correlation was found between the distance to the closest tree and the mean mating-distance calculated for single-tree progenies. The effective pollen dispersal distribution showed a leptokurtic shape, with a large and significant departure from that expected under uniform dispersal. A maximum-likelihood procedure was used to fit an individual pollen dispersal distance probability density function (dispersal kernel). The estimated kernel indicated fairly leptokurtic dispersal (shape parameter b=0.67), with an average pollen dispersal distance of 135 m, and 50% of pollen dispersed beyond 30 m. A marked directionality pattern of pollen dispersal was found, mainly caused by the uneven distribution of trees, coupled with restricted dispersal and unequal male success. Overall, results show that the number and distribution of potential pollen donors in small populations may strongly influence the patterns of effective pollen dispersal.

Chloroplasts↗
PubMed2005

Measuring the genetic structure of the pollen pool as the probability of paternal identity.

Contemporary pollen flow in forest plant species is measured by the probability of paternal identity (PPI) for two randomly sampled offspring, drawn from a single female, and contrasting that with PPI for two random offspring, drawn from different females. Two different estimation strategies have emerged: (a) an indirect approach, using the 'genetic structure' of the pollen received by different mothers and (b) a direct approach, based on parentage analysis. The indirect strategy is somewhat limited by the assumptions, but is widely useful. The direct approach is most appropriate where a large majority of the true fathers can be identified exactly, which is sometimes possible with high-resolution SSR markers. Using the parentage approach, we develop estimates of PPI, showing that the obvious estimates are severely biased, and providing an unbiased alternative. We then illustrate the methods with SSR data from a 36-tree isolated population of Pinus sylvestris from the Meseta region of Spain, for which categorical paternity assignment was available for over 95% of offspring. For all the females combined, we estimate that PPI=0.0425, indicating uneven male reproductive contributions. Different (but overlapping) arrays of males pollinate different females, and for the average female, PPI=0.317, indicating substantial 'pollen structure' for the population. We also relate the direct measures of PPI to those available from indirect approaches, and show that they are generally comparable.

Genetic Variation↗
PubMed2005

Evidence for paternal transmission and heteroplasmy in the mitochondrial genome of Silene vulgaris, a gynodioecious plant.

Gynodioecy refers to the co-occurrence of females and hermaphrodites in the same population. In many gynodioecious plants, sex is determined by an epistatic interaction between mitochondrial and nuclear genes, resulting in intragenomic evolutionary conflict, should the mitochondrial genome be maternally inherited. While maternal inheritance of the mitochondrial genome is common in angiosperms, few gynodioecious species have been studied. Here, the inheritance of the mitochondrial genes atpA and coxI was studied in 318 Silene vulgaris individuals distributed among 23 crosses. While maternal inheritance was indicated in 96% of the individuals studied, one or more individuals from each of four sib groups displayed a genotype that was identical to the father, or that did not match either parent. Given evidence that inheritance is not strictly maternal, it was hypothesized that some individuals could carry a mixture of maternally and paternally derived copies of the mitochondrial genome, a condition known as heteroplasmy. Since heteroplasmy might be difficult to detect should multiple versions of the mitochondrial genome co-occur in highly unequal copy number, a method was devised to amplify low-copy number forms of atpA differentially. Evidence for heteroplasmy was found in 23 of the 99 individuals studied, including cases in which the otherwise cryptic form of atpA matched the paternal genotype. The distribution of shared nucleotide sequence polymorphism among atpA haplotypes and the results of a population survey of the joint distribution of atpA and coxI haplotypes across individuals supports the hypothesis that heteroplasmy facilitates formation of novel mitochondrial genotypes by recombination.

DNA, Mitochondrial↗
PubMed2006

Paternal inheritance in parthenogenetic forms of the planarian Schmidtea polychroa.

Parthenogenesis usually includes clonal inheritance, which is thought to increase the risk of the clonal populations' extinction. Yet many parthenogenetic organisms appear to have survived for extended periods. A possible explanation is that parthenogens occasionally reproduce through sex-like processes. Although there is indirect evidence for occasional sex, the underlying mechanisms are currently unknown. In the present study, we examined sex-like processes in the planarian flatworm Schmidtea (Dugesia) polychroa. Parthenogenetic forms of this species are simultaneous hermaphrodites that require sperm to trigger embryogenesis, whereas paternal genetic material is usually excluded from the oocyte (sperm-dependent parthenogenesis). Based on a comparison of parents and offspring, using highly polymorphic microsatellites, we demonstrate the incorporation of paternal alleles in about 5% of the offspring. We detected two distinct processes: chromosome addition and chromosome displacement. Such rare sexual processes may explain the long-term persistence of the many purely parthenogenetic populations of S. polychroa in northern Europe.

Animals↗
PubMed2005

Association of the paternally transmitted copy of common Valine allele of the Val66Met polymorphism of the brain-derived neurotrophic factor (BDNF) gene with susceptibility to ADHD.

Attention deficit hyperactivity disorder (ADHD) is a common, highly heritable, neurodevelopmental disorder with onset in early childhood. Genes involved in neuronal development and growth are, thus, important etiological candidates and brain-derived neurotrophic factor (BDNF), has been hypothesized to play a role in the pathogenesis of ADHD. BDNF is a member of the neurotrophin family and is involved in the survival and differentiation of dopaminergic neurons in the developing brain (of relevance because drugs that block the dopamine transporter can be effective therapeutically). The common Val66Met functional polymorphism in the human BDNF gene (rs 6265) was genotyped in a collaborative family-based sample of 341 white UK or Irish ADHD probands and their parents. We found evidence for preferential transmission of the valine (G) allele of BDNF (odds ratio, OR=1.6, P=0.02) with a strong paternal effect (paternal transmissions: OR=3.2, P=0.0005; maternal transmissions: OR=1.00; P=1.00). Our findings support the hypothesis that BDNF is involved in the pathogenesis of ADHD. The transmission difference between parents raises the possibility that an epigenetic process may be involved.

Amino Acid Substitution↗
PubMed2001

Mosaic pattern of maternal and paternal keratinocyte clones in normal human epidermis revealed by analysis of X-chromosome inactivation.

During early development of the female embryo, one X-chromosome is randomly inactivated in each cell. As a result of growth, migration, and differentiation, the adult female becomes a mosaic of cells with either the paternal or the maternal X-chromosome inactivated. It is not known what structure the X-chromosome inactivation pattern has in skin of normal individuals. We investigated normal skin from four healthy females, heterozygous for the HUMARA microsatellite on the X-chromosome. Following careful microdissection, DNA from adjacent epidermal samples consisting of approximately 35 basal keratinocytes was digested with the methylation-sensitive enzyme HpaII. The inactivated X-chromosome remained intact due to extensive methylation. The enzyme-digested DNA was amplified using polymerase chain reaction and fragments were analyzed for size. Through examination of adjacent samples and consecutive sections, we found normal human skin to be composed of a fine mosaic of tiles with either maternal or paternal X-chromosome inactivated. The sizes of these tiles were between 20 and 350 basal cells. The method described has the potential to resolve the clonal status in normal as well as pathologic conditions.

Adult↗
PubMed2001

Parentage assignment and extra-group paternity in a cooperative breeder: the Seychelles warbler (Acrocephalus sechellensis).

We describe the development and initial application of a semiautomated parentage testing system in the Seychelles warbler (Acrocephalus sechellensis). This system used fluorescently labelled primers for 14 polymorphic microsatellite loci in two multiplex loading groups to genotype efficiently over 96% of the warbler population on Cousin island. When used in conjunction with the program CERVUS, this system provided sufficient power to assign maternity and paternity within the Seychelles warbler, despite the complications associated with its cooperative breeding system and a relatively low level of genetic variation. Parentage analyses showed that subordinate 'helper' females as well as the dominant 'primary' females laid eggs in communal nests, indicating that the Seychelles warbler has an intermediate level of female reproductive skew, in between the alternative extremes of helper-at-the-nest and joint nesting systems. Forty-four per cent of helpers bred successfully, accounting for 15% of all offspring. Forty per cent of young resulted from extra-group paternity.

Animals↗
PubMed2001

The reproductive biology of Polytrichum formosum: clonal structure and paternity revealed by microsatellites.

Using highly polymorphic microsatellite markers, we assessed clonal structure and paternity in a population of the bryophyte species Polytrichum formosum. Identical multilocus genotypes of individual shoots were almost never observed in spatially separated cushions, but were found to be highly clustered within moss cushions. Therefore, asexual reproduction through dispersal of gametophyte fragments is not very important in P. formosum. However, asexual reproduction on a very localized scale through vegetative growth of genets (branching of gametophytes via clonal growth of rhizomes) is very extensive. The patchy spatial distribution of genets and the absence of intermingling among genets suggest that this species follows a 'phalanx' clonal growth strategy. Vegetative proliferation of genets will increase their size, and, consequently, will have considerable fitness consequences for individuals in terms of increased genet longevity and reproductive output. Although paternity analysis of sporophytes confirmed male genet size, i.e. gamete production, to be an important determinant of male reproductive fitness, it also showed that the spatial distance to female genets is the predominant factor that governs male reproductive success. Moreover, we showed that male gamete dispersal distances in P. formosum are much further than generally assumed, and are in the order of metres rather than centimetres. Combining the findings, we conclude that the high genotypic diversity observed for this facultatively clonal species is most likely explained by a preponderance of sexual reproduction over clonal reproduction.

Bryopsida↗
PubMed1997

Glomus tumours and genomic imprinting: influence of inheritance along the paternal or maternal line.

Two new families with glomus tumours and two additions to earlier publications are presented. The pattern of inheritance is autosomal dominant. Familial glomus tumours are inherited almost exclusively via the paternal line, a finding inconsistent with autosomal dominant transmission. This can be explained by genomic imprinting. The maternally derived gene is inactivated during female oogenesis and can be reactivated only during spermatogenesis. Two different loci have been assigned, one to a 5 cM region of chromosome 11q13.1 and one to 11q22.3-q23.3. Genomic imprinting has already been found for the distal locus and here we demonstrate that the proximal locus is subject to genomic imprinting too. Genomic imprinting has considerable implications for genetic counselling in families with glomus tumours. In addition to this the sex ratio among affected offspring appears to be influenced by the paternal or maternal origin of the gene of the transmitting father.

Aged↗
PubMed1999

Molecular anatomy of an onychophoran: compartmentalized sperm storage and heterogeneous paternity

Onychophorans (peripatus or velvet worms) show extraordinarily high local endemism, and cryptic species are common. As part of a programme addressing issues of endemicity at hierarchical spatial scales, we investigated reproduction in Euperipatoides rowelli (Onychophora: Peripatopsidae) using microsatellite analysis. This species is ovoviviparous, and females have up to 70 embryos in their uteri simultaneously. Batches of undeveloped and well-developed embryos may be present in the uteri of a female. Paired ovaries lead via a common oviduct into paired uteri, each of which has a spermatheca (sperm storage organ). Insemination in E. rowelli is dermal-haemocoelic: spermatophores are placed on the skin of the female, the body wall is breeched, and sperm are released into the haemocoel through which they migrate to the spermathecae. There is no obvious mechanism to prevent sperm mixing, yet microsatellite analysis indicated that offspring in a female's paired reproductive tracts can be sired by different males, and that the paired spermathecae can contain sperm from different males. More than 70% of females had broods with multiple paternity. The data are consistent with the potential for female postcopulatory influence over fertilizations: in particular, compartmentalization of sperm from different males into different spermathecae. Female control of fertilizations could lead to benefits including increased diversity of offspring, minimization of maternal-paternal genetic incompatibility, and influence on offspring genotypes. Multiple mating alone may increase the genetic diversity of offspring: this could be of importance in E. rowelli, which has very small genetic neighbourhoods and low genetic marker diversity.

Journal Article↗
PubMed2000

Estimation of gene flow in the tropical-rainforest tree Neobalanocarpus heimii (Dipterocarpaceae), inferred from paternity analysis.

Pollen flow and population genetic structure among 30 potentially flowering individuals of Neobalanocarpus heimii, a tropical emergent tree, were investigated in a lowland tropical rainforest of Malaysia using microsatellite polymorphism. The 248 offspring in the vicinity of five reproductive trees of the 30 potentially flowering trees were used in paternity analysis for pollen-flow study. Four primer pairs, developed in different species of dipterocarps, were adopted to detect microsatellite polymorphism. Based upon microsatellite polymorphism, pollen flow and seed migration were detected. Pollen-flow events of more than 400 m were observed directly, based on paternity analysis in the study plot. The estimated average mating distance of the five reproductive trees was 524 m. This result suggests that reproduction of this species is mediated by a long-distance pollinator. The haplotypes of some offspring were not compatible with the nearest reproductive tree. Thus, the results suggest that some seeds are dispersed by a seed dispersal vector. Investigation of genetic structure showed significant and negative correlation of genetic relatedness and spatial distances between the 30 potentially flowering trees, but this correlation was weak. We suggest that long-distance gene flow and seed migration are responsible for the poorly developed genetic structure of this species.

Ecosystem↗