CYTOGENETIC FEATURES OF HUMAN HEAD AND BODY LICE (PHTHIRAPTERA: PEDICULIDAE).

MARÍA JOSÉ BRESSA; ALBA GRACIELA PAPESCHI; ARIEL CEFERINO TOLOZA

JOURNAL OF MEDICAL ENTOMOLOGY

ENTOMOLOGICAL SOC AMER

Lugar: Lanham; Año: 2015 vol. 52 p. 918 - 924

0022-2585

Abstract. The genus Pediculusthat parasitize humans comprise two subspecies: the head lice Pediculus humanus capitis and the bodylice Pediculus humanus humanus.Despite the two hundred years of the first description of this two species,there is still a long debate about their taxonomic status. Some authorsproposed that these organisms are separate species, conspecifics or grouped inclades.. The sequencing of both forms indicated that the difference betweenthem is one gene absent in the head louse. However, their chromosomal numberremains to be determined. In this study, we described the male and femalekaryotypes, and male meiosis of head and body lice, and examined the chromatinstructure by means of C-banding. In P. h.humanus and P. h. capitis, the diploid chromosome complement was 2n = 12 inboth sexes. In oogonial prometaphase and metaphase and spermatogonialmetaphase, it is evident that chromosomes lack of a primary constriction. Noidentifiable sex chromosomes or B chromosomes were observed in head and bodylice. Neither chiasmata nor chromatin connections between homologouschromosomes were detected in male meiosis. The meiotic behaviour of thechromosomes showed that they are holokinetic. C-banding revealed the absence ofconstitutive heterochromatin. Our results provide relevant information to beused in mapping studies of genes associated with sex determination andenvironmental sensing and response.