During meiosis, pairs of homologous chromosomes often twist around each other and remain in contact during the process of separation. The point at which paired chromosomes remain in contact is known as a chiasma, because it has a cross-shaped...

A chiasma (Greek χίασμα, related to the Greek letter Χ) means "crossing." In anatomy, it refers to the point where two (or more) nerves or ligaments cross or intersect. In genetics, it is a technical term for the point where two chromatids are...

Key words. Central-marginal distribution, chiasmata, Dichroplus, latitudinal gradient, morphological variability, recombination, Robertsonian translocation Abstract. The grasshopper Dichroplus pratensis Bruner is polymorphic and polytypic for a complex Robertsonian system. In this species, centric fusions induce changes in number and position of chiasmata, and thus...

ABSTRACT Crossover interference in meiosis is often modeled via stationary renewal processes. Here we consider a new model to incorporate the known biological feature of "obligate chiasma" whereby in most organisms each bivalent almost always has at least one crossover. The initial crossover...