Among vertebrates, teleost fish exhibit a considerably wide range of sex determination patterns that may be influenced by extrinsic parameters. However even for model fish species like the zebrafish Danio rerio the precise mechanisms involved in primary sex determination have not been studied extensively. The zebrafish, a gonochoristic species, is lacking discernible sex chromosomes and the sex...

Studies of the reproductive biology of the nematode Caenorhabditis elegans are providing valuable insights into the evolution and diversity of reproductive strategies [1,2]. The successful production of progeny in any species also highlights many fundamental problems in cell biology. Research on the amoeboid sperm of nematodes addresses a number of issues of broad biological significance, inclu...

Papaya is a semi-woody tree that produces fruit rich in vitamins and minerals. It is trioecious with male, female, and hermaphrodite plants. Though many theories have been suggested in the past, papaya sex is determined by a pair of nascent sex chromosomes; females have two X chromosomes, males have an X and a Y, and hermaphrodites have an X and a Y, which varies slightly from the male Y. Any c...

Kryptolebias marmoratus, a small killifish that lives in mangrove habitat from southern Florida to Brazil, is one of the planet's only known self-fertilizing hermaphroditic vertebrates. Generation after generation, hermaphroditic individuals simultaneously produce sperm and eggs and internally self-fertilize to produce what are, in effect, highly inbred clones of themselves. Although population...

In the model organism Caenorhabditis elegans, a class of small molecule signals called ascarosides regulate development, mating, and social behaviors. Ascaroside production has been studied in the predominant sex, the hermaphrodite, but not in males, which account for less than 1% of wild-type worms grown under typical laboratory conditions. Using HPLC-MS-based targeted metabolomics, we show th...

Changes in organ morphology have been essential to the evolution of novel body forms and in permitting organisms to invade new ecological niches. Changes in the arrangement of cells and tissues and in the regulation of morphological movements are fundamental to evolutionary transitions of organ shape and function. However, little is known about the genetic and developmental control of these cha...