TY - JOUR

T1 - L chromosome behaviour and chromosomal imprinting in Sciara Coprophila

AU - Singh, Prim B.

AU - Belyakin, Stepan N.

N1 - Publisher Copyright: © 2018 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2018/9/1

Y1 - 2018/9/1

N2 - The retention of supernumerary chromosomes in the germ-line of Sciara coprophila is part of a highly-intricate pattern of chromosome behaviours that have fascinated cytogeneticists for over 80 years. Germ-line limited (termed L or “limited”) chromosomes are cytologically heterochromatic and late-replicating, with more recent studies confirming they possess epigenetic hallmarks characteristic of constitutive heterochromatin. Little is known about their genetic constitution although they have been found to undergo cycles of condensation and de-condensation at different stages of development. Unlike most supernumeraries, the L chromosomes in S. coprophila are thought to be indispensable, although in two closely related species Sciara ocellaris and Sciara reynoldsi the L chromosomes, have been lost during evolution. Here, we review what we know about L chromosomes in Sciara coprophila. We end by discussing how study of the L chromosome condensation cycle has provided insight into the site and timing of both the erasure of parental “imprints” and also the placement of a putative “imprint” that might be carried by the sperm into the egg.

AB - The retention of supernumerary chromosomes in the germ-line of Sciara coprophila is part of a highly-intricate pattern of chromosome behaviours that have fascinated cytogeneticists for over 80 years. Germ-line limited (termed L or “limited”) chromosomes are cytologically heterochromatic and late-replicating, with more recent studies confirming they possess epigenetic hallmarks characteristic of constitutive heterochromatin. Little is known about their genetic constitution although they have been found to undergo cycles of condensation and de-condensation at different stages of development. Unlike most supernumeraries, the L chromosomes in S. coprophila are thought to be indispensable, although in two closely related species Sciara ocellaris and Sciara reynoldsi the L chromosomes, have been lost during evolution. Here, we review what we know about L chromosomes in Sciara coprophila. We end by discussing how study of the L chromosome condensation cycle has provided insight into the site and timing of both the erasure of parental “imprints” and also the placement of a putative “imprint” that might be carried by the sperm into the egg.

KW - Controlling element

KW - Heterochromatin

KW - Maternal X chromosome

KW - Parent-of-origin effects

KW - Paternal X chromosome

KW - Supernumerary chromosomes

KW - parent-of-origin effects

KW - DIPTERA

KW - X-CHROMOSOME

KW - GERM-LINE

KW - SEX

KW - ELIMINATION

KW - supernumerary chromosomes

KW - HISTONE H3 PHOSPHORYLATION

KW - FLIES

KW - controlling element

KW - heterochromatin

KW - HETEROCHROMATIN

KW - MEIOSIS

KW - maternal X chromosome

KW - paternal X chromosome

KW - INHERITANCE

UR - http://www.scopus.com/inward/record.url?scp=85053045676&partnerID=8YFLogxK

U2 - 10.3390/genes9090440

DO - 10.3390/genes9090440

M3 - Review article

C2 - 30177635

AN - SCOPUS:85053045676

VL - 9

JO - Genes

JF - Genes

SN - 2073-4425

IS - 9

M1 - 440

ER -