نتایج جستجو برای: parthenogenetic
تعداد نتایج: 1519 فیلتر نتایج به سال:
Chimeras were made from parthenogenetic and fertilized cleavage-stage mouse embryos. The perinatal mortality was high. The parthenogenetic contributions to different tissues at birth ranged from 0 to 50%. No selection of parthenogenetic cells was observed in the pigmentation of the coat, but this does not exclude that such selection could act in other tissues. The weight of chimeras at birth ne...
The developmental potential of primitive ectoderm cells lacking paternal chromosomes was investigated by examining the distribution of parthenogenetic cells in chimeras. Using GPI-1 allozymes as marker, parthenogenetic cells were detected in most organs and tissues in adult chimeras. However, these cells were under severe selective pressure compared with cells from normal fertilized embryos. In...
Even though pure parthenogenetic mouse embryos die shortly after implantation, their cells are capable of participating in normal development of chimaeras when aggregated with fertilized embryos. Here we present data on parthenogenetic contribution to the oocyte populations measured by progeny tests in female chimaeras, and on distribution of parthenogenetic cells among the different organs by ...
The objective of this study was to examine the effect of different sera and serum-like substances on the preimplantation development of porcine parthenogenetic embryos. Chemically activated (calcium ionophore A23187+cytochalasin B) pig oocytes were pre-cultured for five days. On day 5, the parthenogenetic embryos were treated with porcine follicular fluid (PFF), fetal bovine serum (FBS), horse ...
A diploid parthenogenetic strain of Drosophila mercatorum was outcrossed to produce genetic variance among the impaternate female offspring. Selection experiments were carried out for reluctance of the parthenogenetic females to mate. After only two cycles of selection, a parthenogenetic strain which is significantly less receptive to males from three different bisexual strains was obtained. It...
Laboratory generation of new parthenogenetic lineages supports contagious parthenogenesis in Artemia
Contagious parthenogenesis-a process involving rare functional males produced by a parthenogenetic lineage which mate with coexisting sexual females resulting in fertile parthenogenetic offspring-is one of the most striking mechanisms responsible for the generation of new parthenogenetic lineages. Populations of the parthenogenetic diploid brine shrimp Artemia produce fully functional males in ...
Drosophila mercatorum is a sexual species that can reproduce parthenogenetically in the laboratory. A previous study showed that a natural population of D. mercatorum inhabiting the Kamuela garbage dump on the Island of Hawaii could produce both viable parthenogenetic adults and self-sustaining parthenogenetic lines. The present study deals with a second screen for parthenogenesis and an isozym...
Melatonin is a unique multifunctional molecule that mediates reproductive functions in animals. In this study, we investigated the effects of melatonin on bovine parthenogenetic and androgenetic embryonic development, oocyte maturation, the reactive oxygen species (ROS) levels in parthenogenetic and androgenetic embryos and cumulus-oocyte complexes (COCs) hormone secretion with melatonin supple...
The availability of high quality resources is an important factor driving community structure and reproductive mode of animals. Parthenogenetic reproduction prevails when resources are available in excess, whereas sexuality correlates with resource shortage. We investigated the effect of resource availability on the community structure of oribatid mites in a laboratory experiment. Availability ...
The problem of the maintenance of anisogamous sex is addressed by considering the effect of fertilization on the fitness of parthenogenetic females when such fertilization yields inviable triploid progeny. We consider four types of parthenogenesis: (i) apomixis, (ii) homogametic amphimixis, (iii) heterogametic amphimixis, and (iv) homogametic automixis. Homozygous sexual populations are genetic...
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