The zebra shark Stegostoma tigrinum , a popular aquarium fish, is an endangered species that known to readily reproduce both sexually and through facultative parthenogenesis while in human care. Artificial insemination trials took place between 2011 2013 resulted the hatching of 2 produced (herein heterozygotes) 10 parthenogenetic sharks allowed for retrospective comparison growth, feeding long...

in vitro maturation (ivm) was carried out in the presence of different concentrations (10, 50, 100 or 200 µm) of α-linolenic acid (ala). embryonic cleavage, blastocyst formation following parthenogenetic activation (pa) and in vitro fertilization (ivf), and numbers of total and apoptotic cells in blastocyst were then determine for the 50 μm concentration and compared with the control group. out...

The cytoskeletal organization of the mouse egg changes during ageing in vivo and in vitro. The earliest change observed is the disappearance of the microfilament-rich area overlying the meiotic spindle. This is followed by the migration of the spindle towards the centre of the egg. Finally the spindle breaks down and the chromosomes are no longer organized on a metaphase plate. This spindle dis...

The evolution of obligate parthenogenesis may induce the degeneration of female mating ability and subsequently affect the morphology of the female reproductive organs related to mating and ⁄or sperm storage. Here, we investigated the size and structure of the sperm storage organ, the spermatheca, in three thelytokous parthenogenetic myrmicine ant species, Pristomyrmex punctatus, Pyramica membr...

Whiptail lizards provide a unique system to study evolution of brain mechanisms because both ancestral (sexual) and descendant (parthenogenetic) species exist. Parthenogenetic whiptails enable us to avoid the two major confounds in sex differences research - males and females that differ both genetically and hormonally. Parthenogens are females that reproduce clonally, yet display alternately f...

Parthenogenetic and normal blastocysts were compared using differential display analysis as a means to identify new imprinted genes. A single gene was identified with increased expression in parthenogenetic blastocysts, suggesting it might be an imprinted gene expressed from the maternally inherited allele. The gene, named Bex1 (brainexpressedX-linked gene), maps near Plp on the mouse X chromos...