in assisted reproduction techniques (art) settings, reactive oxygen species (ros) can be produced from endogenous and exogenous sources during in vitro manipulation. endogenous sources of ros include gametes and embryo, whereas exogenous sources are oxygen tension, light exposure, culture media, and the nature of some protocols, such as centrifugation or cryopreservation. elevated ros productio...

Sexuality in the marine araphid diatom Tabularia involves an unusual type of gamete, not only among diatoms but possibly in all of nature. The non-flagellated male gamete is free and vigorously motile, propelled by pseudopodia. However, the cues (if any) in their search for compatible female gametes and the general search patterns to locate them are unknown. We tracked and compared male gamete ...

We address various statistical aspects of biological parentage in multi-offspring broods that arise via multiple paternity or multiple maternity and, hence, consist of mixtures of full- and half-sibs. Conditioned on population genetic parameters, computer simulations described herein permit estimation of: (1) the mean number of offspring needed to detect all parental gametes in a brood and (2) ...

The Ethics Committee supports disclosure from parents to offspring about the use of donor gametes in their conception. The merits of further disclosure are discussed, and suggestions are made for policies for programs and sperm banks.

Bateman identified two aspects of sexual selection. The first, called Bateman's principle, is that sexual selection favors increased promiscuity of males but not of females as a result of differences in parental investment in gametes. The second is that the variance in mate number of males is the fundamental cause of a sex difference in fitness variance. We argue that Bateman's insight about th...

BACKGROUND Flowering plant seeds originate from a unique double-fertilization event, which involves two sperm cells and two female gametes, the egg cell and the central cell. For many years our knowledge of mechanisms involved in angiosperm fertilization remained minimal. It was obvious that several signals were required to explain how the male gametes are delivered inside the maternal reproduc...

Eyespot membranes in zoospores, and male and female gametes of the green alga Ulva lactuca, were studied comparatively by the freeze-fracture technique. The plasmalemma and the outer chloroplast envelope membrane overlying the eyespot lipid globules are specialized in all 3 types of reproductive cells. In the eyespot region the protoplasmic face (PF) of the outer chloroplast envelope membrane c...