Parthenogenesis in vertebrates is considered an evolutionary novelty. In snakes, all of which exhibit genetic sex determination with ZZ : ZW sex chromosomes, this rare form of asexual reproduction has failed to yield viable female WW offspring. Only through complex experimental manipulations have WW females been produced, and only in fish and amphibians. Through microsatellite DNA fingerprintin...

With a few rare exceptions, the vast majority of animals reproduce sexually. Some species have, however, evolved alternative modes of reproduction by shifting from classical bisexuality to unorthodox reproductive systems, like parthenogenesis, gynogenesis, or hybridogenesis. Under hybridogenesis, both the maternal and paternal genomes are expressed in somatic tissues, whereas the germline is pu...

Jacques Loeb [5] broadened and corrected his earlier claims concerning artificial parthenogenesis [6] in sea urchins in a series of experiments in 1900. He published these findings, ?Further Experiments on Artificial Parthenogenesis [4] and the Nature of The Process of Fertilization,? in a 1900 issue of The American Journal of Physiology. His new results amended those from earlier experiments h...

the aim of this study was to compare the effect of time of parthenogenetic activation (22 hr versus 27 hr after in vitro maturation-ivm) on in vitro development of ovine oocytes using either single (ionomycin 5 ?m for 5 min or ethanol 7% for 7 min) or combined (ionomycin and ethanol with 6-dmap 2 mm for 3 hr) activation treatments. the abattoir-derived in vitro matured activated oocytes were cu...

According to the firm life cycle theory, companies go through certain behavioral patterns in various stages of their life. A thorough understanding and recognition of these behavioral patterns, new investment in assets and the optimal use of assets can considerably enhance the capital productivity. In the current study, the relationship between the stages of firm life cycle and capital producti...