نتایج جستجو برای: parthenogenetic

تعداد نتایج: 1519  

Journal: :Development 2010
Takafusa Hikichi Hiroshi Ohta Sayaka Wakayama Teruhiko Wakayama

Mammalian parthenogenetic embryos invariably die in mid-gestation from imprinted gene defects and placental hypoplasia. Based on chimera experiments, trophoblastic proliferation is supposed to be inhibited in the absence of a male genome. Here, we show that parthenogenetic mouse embryonic cell nuclei can be reprogrammed by serial rounds of nuclear transfer without using any genetic modification...

2009
Mesut ÇEVİK Arzu TAŞ Tolga AKKOÇ Haydar BAĞIŞ Sezen ARAT

The objective of this study was to determine the effects of 3 chemical agents used sequentially and electrical stimuli on parthenogenetic activation of in vitro matured bovine oocytes and comparison with a standard IVF protocol for embryo developmental rates. For this purpose, oocytes were matured in tissue culture medium-199 (TCM-199) at 39 °C and 5% of CO2 in humidified air. For IVF, matured ...

2015
K. Sekiné F. Hayashi K. Tojo

The burrowing polymitarcyid mayfly Ephoron shigae is distributed across Japan, Korea, northeast China and far east Russia. Some populations are bisexual, and others are unisexual, i.e. geographically parthenogenetic throughout Japan. In general, parthenogenetic organisms are often found in harsh environments, such as at high latitudes and altitudes, in xeric as opposed to mesic conditions, in i...

Journal: :Genetics 1971
K M Darcey E G Buss S E Bloom M W Olsen

PPROXIMATELY 17% of the eggs laid by non-mated Beltsville Small A White (BSW) turkeys showed some type (e.g., membranes, blood, embryos) of development upon incubation ( OLSEN and MARSDEN 1953,1954). The question arose as to whether the cells in such unfertilized eggs were haploid or diploid. YAO and OLSEN (1955) reported finding diploid chromosome numbers in embryonic tissue of parthenogenetic...

2007
J. Petr E. Chmelíková L. Tůmová M. Ješeta

Parthenogenetic activation of mammalian oocytes with artificial stimuli is commonly applied in various reproductive biotechniques, e.g. cloning using nuclear transfer. For this reason, many studies focus on oocyte activation in vitro. Recently we have described the activation of pig oocytes using nitric oxide. This activating stimulus is very specific in many aspects. However, it does not provi...

Journal: :Mechanisms of Development 2015
Georgia Pennarossa Sara Maffei Gianluca Tettamanti Terenzio Congiu Magda deEguileor Fulvio Gandolfi Tiziana A.L. Brevini

Parthenogenetic cells, obtained from in vitro activated mammalian oocytes, display multipolar spindles, chromosome malsegregation and a high incidence of aneuploidy, probably due to the lack of paternal contribution. Despite this, parthenogenetic cells do not show high rates of apoptosis and are able to proliferate in a way comparable to their biparental counterpart. We hypothesize that a serie...

2011
David L. Porter Jon Martin

Micropsectra sedna (Oliver, 1976) is a parthenogenetic midge from the Canadian Arctic. The parthenogenetic mechanism is apomictic thelytoky, with a restitutional division during oogenesis, as found in other parthenogenetic Chironomidae. It is triploid, with two similar chromosome sets, and the third is relatively dissimilar, pairing little with the diploid set. Two karyotypes were observed: a s...

Journal: :Journal of theoretical biology 2009
David W Crowder Yves Carrière

Genetically modified (GM) crops are used extensively worldwide to control diploid agricultural insect pests that reproduce sexually. However, future GM crops will likely soon target haplodiploid and parthenogenetic insects. As rapid pest adaptation could compromise these novel crops, strategies to manage resistance in haplodiploid and parthenogenetic pests are urgently needed. Here, we develope...

2014
Helge von Saltzwedel Mark Maraun Stefan Scheu Ina Schaefer

Parthenogenetic lineages may colonize marginal areas of the range of related sexual species or coexist with sexual species in the same habitat. Frozen-Niche-Variation and General-Purpose-Genotype are two hypotheses suggesting that competition and interclonal selection result in parthenogenetic populations being either genetically diverse or rather homogeneous. The cosmopolitan parthenogenetic o...

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