Heteromorphic sex chromosomes: sex chromosomes that are morphologically distinct. Sex determination can also be regulated differently in the soma versus the germ line of the same species . The bisection of Adam links the Biblical account to an incident in Plato's Symposium, in which Aristophanes describes the origin of the sexes.
At the molecular level, one route to anisogamy is by the incorporation of genes controlling gamete size into the MAT region . Importantly, the evolution of anisogamy does not require temperature dependent sex determination humans cast in Baton Rouge evolution of separate sexes, because hermaphrodites can produce both sperm and eggs.
Curr Top Dev Biol 41— Temperature-dependent sex determination TSD is not an option for mammals and birds, as they control their own internal temperature within a narrow range. In many animals, sex determination involves the entire genome. It might be surprising that there seems to have been little attempt to study the role of mitochondria—often described as the powerhouses of cells—in sex determination, either during normal development, or to discover possible causative agents for disorders of sexual development.
Transitions from or to haplodiploidy require changes in genetic architecture and meiotic mechanisms, which are likely more complex than a simple change in a master-switch sex-determining gene. Transitions versus differentiation of sex chromosomes. After Zeus cut them in half and Apollo healed their wounds, the two halves came together in mutual embraces.
It should perhaps be admitted that during the years of intensive research into genes and genomes, the cytoplasm has been unduly neglected. The nature and evolution of sex-determining genes and pathways Some taxa have master-switch sex-determining genes that are highly conserved, such as the Sry gene in nearly all mammals .