Inheritance of plastids in interspecific hybrids of blue spruce and white spruce

Summary Chloroplast DNA (cpDNA) was purified from blue spruce (Picea pungens Engelm.) and white spruce [P. glauca (Moench) Voss], and was digested with several different restriction endonucleases. Restriction fragment length polymorphisms (RFLPs) were identified that differentiated the cpDNA of both species. Intraspecific conservation of the RFLPs that differentiated each species was confirmed by examining trees from across the natural range of each species. Ten F₁ hybrids were examined, and the cpDNA from each showed the banding pattern of the paternal species. Cloned Petunia cpDNA containing part of the rbcL gene hybridized to polymorphic bands, while a cloned maize mtDNA probe of the coxII gene failed to hybridize to any band.     

Social and reproductive behavior of three mouthbrooding cardinalfishes,Apogon doederleini,A. niger and A. notatus

Synopsis Social and reproductive behavior of three paternal mouthbrooding cardinalfishes (Apogonidae) were investigated in the shallow marine waters of Shirahama, Japan. The solitary species Apogon doederleini and A. niger bred in transient pairs, in which a male and female associated for only a few hours of each afternoon on less than 5 successive days. The prespawning behavior was the same as the courtship display on days prior to spawning. After spawning, egg-incubating males were usually left alone. The gregarious species Apogon notatus formed territorial lasting pairs, which resided at given sites from dawn to dusk on each day during a period of a month or more. After spawning, the egg-incubating male either continued to stay with his mate in the territory, or left it to enter into an aggregation. In the latter case, the female continued to reside in the territory, pairing with a new male whom she brought from an aggregation. It is suggested that in paternal apogonids the prolonged pair bond and territoriality should have developed only in gregarious species as secondary adaptation for reproductive success: to avoid conspecific interference during spawning.     

Filial cannibalism by mouthbrooding males of the cardinal fish,Apogon doederleini, in relation to their physical condition

Synopsis Paternal brood cannibalism was observed in a population ofApogon doederleini in Shikoku Island, Japan. Of 361 egg masses mouthbrooded by males, 47 disappeared within a day of spawning. A stomach check with a syringe ascertained that they had been consumed by the males. The frequency of this cannibalism increased as the breeding season advanced. As males completed 4–7 breeding cycles in a breeding season and spent 80% of the time mouthbrooding without taking ordinary food, their physical condition deteriorated greatly late in the breeding season. We concluded that parental physical condition is an important factor in the occurrence of brood cannibalism.     

牵牛属质体DNA的父系遗传

利用限制性片段长度多态性（ＲＦＬＰ）技术研究了牵牛属（Ｐｈａｒｂｉｔｉｓ）植物质体ＤＮＡ 的遗传方式。结果表明,在牵牛（Ｐ． ｎｉｌ）×大花牵牛（Ｐ． ｌｉｍｂａｔａ）和大花牵牛×牵牛中,质体ＤＮＡ 为父系遗传。在大花牵牛×牵牛中,质体ＤＮＡ还有可能为双亲遗传。研究证明牵牛属为被子植物中具有质体父系遗传方式的第三个属。牵牛属质体父系遗传机制尚不清楚,作者认为母系质体及其ＤＮＡ 在受精后的释稀、排除和／或降解可能是质体父系遗传的基础     

Induction of paternal genome loss by the paternal-sex-ratio chromosome and cytoplasmic incompatibility bacteria (Wolbachia): A comparative study of early embryonic events

Paternal genome loss (PGL) during early embryogenesis is caused by two different genetic elements in the parasitoid wasp, Nasonia vitripennis. Paternal sex ratio (PSR) is a paternally inherited supernumerary chromosome that disrupts condensation of the paternal chromosomes by the first mitotic division of fertilized eggs. Bacteria belonging to the genus Wolbachia are present in Nasonia eggs and also disrupt paternal chromosome condensation in crosses between cytoplasmically incompatible strains. Cytoplasmic incompatibility Wolbachia are widespread in insects, whereas PSR is specific to this wasp. PGL results in production of male progeny in Nasonia due to haplodiploid sex determination. The cytological events associated with PGL induced by the PSR chromosome and by Wolbachia were compared by fluorescent light microscopy using the fluorochrome Hoescht 33258. Cytological examination of eggs fertilized with PSR-bearing sperm revealed that a dense paternal chromatin mass forms prior to the first metaphase. Quantification of chromatin by epifluorescence indicates that this mass does undergo replication along with the maternal chromatin prior to the first mitotic division but does not replicate during later mitotic cycles. Contrary to previous reports using other staining methods, the paternal chromatin mass remains condensed during interphase and persists over subsequent mitotic cycles, at least until formation of the syncytial blastoderm and cellularization, at which time it remains near the center of the egg with the yolk nuclei. Wolbachia-induced PGL shows several marked differences. Most notable is that the paternal chromatin mass is more diffuse and tends to be fragmented during the first mitotic division, with portions becoming associated with the daughter nuclei. Nuclei containing portions of the paternal chromatin mass appear to be delayed in subsequent mitotic divisions relative to nuclei free of paternal chromatin. Crosses combining incompatibility with PSR were cytologically similar to Wolbachia-induced PGL, although shearing of the paternal chromatin mass was reduced. Wolbachia may, therefore, block an earlier stage of paternal chromatin processing in the fertilized eggs than does PSR. © 1995 Wiley-Liss, Inc.     

Female sand gobies prefer good fathers over dominant males

Female preference for males successful in male-male competition is generally assumed to result in mating with high quality males. Here I report results from an experiment disentangling the effects of intra- and intersexual selection in the sand goby, Pomatoschistus minutus, a marine fish that exhibits paternal care. I show that large males are successful in male–male competition, but contrary to what one would expect, dominants are not preferred by females and are not better at taking care of the eggs. Female preference, however, correlated with the subsequent hatching success of the eggs. Thus, female choice selects for good parenting. Hence, direct benefits in the form of superior paternal care can explain female choice in this species, supporting a good parent process of sexual selection. However, choosing on the outcome of male–male competition does not enable females to mate with the ''best'' males.     

Paternal regulation of seed development in wheat hybrids

Summary Diallel crosses among Triticum boeoticum (4 lines from different geographical areas), T.urartu, Aegilops squarrosa and Ae. speltoides exhibited reciprocal differences in hybrid seed morphology, endosperm development, and embryo viability. T. urartu and Ae. squarrosa as females with T. boeotiaum and Ae. speltoides lead to shrivelled inviable seed. T.boeoticum accessions as female with Ae.speltoides also lead to shrivelled seeds. The reciprocal crosses produced plump seeds which either resembled the maternal parent or showed size differences. By altering the endospermic genome ratios, hybrid seeds with 1 (PF)/1 (PM) showed extreme shrivelling whereas those with 4 (PF)/1 (PM) were medium shrivelled to plump. Genetic experiments involving hybrids of T. boeoticum, T. urartu and T. monococcum showed that a factor is present in pollen or male gametes, which shows dosage effect and which, by interacting with the maternal genome, leads to endosperm abortion.     

Paternal reciprocal translocation t(11;16)(p13;q24.3) in a Silver-Russel syndrome patient

We describe a 7-month-old male child with Silver-Russel syndrome (SRS) phenotype, presented with two major clinical features: low birth weight, short stature, and minor features, such as macrocephaly, clinodactyly, essential for the diagnosis of SRS. Routine cytogenetic studies with GTG-banding showed 46,XY,t(11;16)(p13;q24.3). Fluorescence in situ hybridisation (FISH) with single copy probes BAC (11p13) and PAC (16q24.3), showed a reciprocal translocation. Chromosomal analysis of the mother was normal and the phenotypically normal father had apparently identical translocation t(11;16)(p13;q24.3). The disruption of growth factor genes at 11p and 16q breakpoint regions due to reciprocal translocation in the father might have caused SRS phenotype in the child.     

Strict paternal transmission of mitochondrial DNA of Chlamydomonas species is explained by selection against maternal nucleoids

Summary.  The non-Mendelian inheritance of organelle DNA is common in most plants and animals. Here we examined inheritance mechanisms involved in the transfer of mitochondrial DNA. We successively backcrossed (to F₅) two interfertile strains of the unicellular isogamous haploid algae Chlamydomonas reinhardtii and Chlamydomonas smithii to match nuclear backgrounds and examine transmission patterns of mitochondrial DNA by PCR analysis of cob gene sequences. Mitochondrial DNA was strictly transmitted paternally. To investigate the behavior of parental mitochondrial DNA, we used F₅ progeny to form zygotes and isolated single zygotes. The results showed selective disappearance of maternal mitochondrial nucleoids occurred between 3 and 6 h after zygote formation. Received July 11, 2002; accepted September 28, 2002; published online June 13, 2003 RID="*" ID="*" Correspondence and reprints: Laboratory of Cell and Functional Biology, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan.     

Hormonal correlates of human paternal interactions: a hospital-based investigation in urban Jamaica

To expand our understanding of the neuroendocrine mechanisms underlying human fatherhood, including its cross-cultural expression, we investigated the hormonal correlates of fatherhood in the greater Kingston, Jamaica area. We recruited 43 men, aged 18-38, to participate: 15 single men; 16 "coresidential" fathers (men who live with their adult female partner and youngest child); and 12 "visiting" fathers (men who live apart from their adult female partner and youngest child). The research protocol entailed biological sampling before and after a 20-min behavioral session during which single men sat alone and fathers interacted with their partner and youngest child. Hormone measures relied upon minimally invasive techniques (salivary testosterone and cortisol, finger prick blood spot prolactin, urinary oxytocin and vasopressin). Results revealed significant group differences in average male testosterone levels (p=0.006), with post hoc contrasts indicating that visiting fathers had significantly (p<0.05) lower testosterone levels than single men. Prolactin profiles also differed significantly across groups (p=0.010) whereby post hoc contrasts showed that prolactin levels of single men declined significantly compared with the flat levels of visiting fathers (p<0.05). No group differences in cortisol, oxytocin or vasopressin levels were observed. However, among fathers, vasopressin levels were significantly and negatively (r=-.431, p=0.022) correlated with the age of a man's youngest child. These results thus implicate lower testosterone levels as well as prolactin and vasopressin in human fatherhood. These findings also highlight the importance of sociocultural context in human fatherhood while exhibiting parallels with existing data on the non-human vertebrate hormonal bases of paternal care.