TY - JOUR

T1 - B chromosomes in grasshoppers

T2 - Different origins and pathways to the modern Bs

AU - Jetybayev, Ilyas Yerkinovich

AU - Bugrov, Alexander Gennadievich

AU - Dzyubenko, Victoria Vladimirovna

AU - Rubtsov, Nikolay Borisovich

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

PY - 2018/10/18

Y1 - 2018/10/18

N2 - B chromosomes (Bs) were described in most taxa of eukaryotes and in around 11.9% of studied Orthopteran species. In some grasshopper species, their evolution has led to many B chromosome morphotypes. We studied the Bs in nine species (Nocaracris tardus, Nocaracris cyanipes, Aeropus sibiricus, Chorthippus jacobsoni, Chorthippus apricarius, Bryodema gebleri, Asiotmethis heptapotamicus songoricus, Podisma sapporensis, and Eyprepocnemis plorans), analyzing their possible origin and further development. The studied Bs consisted of C-positive or C-positive and C-negative regions. Analyzing new data and considering current hypotheses, we suggest that Bs in grasshoppers could arise through different mechanisms and from different chromosomes of the main set. We gave our special attention to the Bs with C-negative regions and suggest a new hypothesis of B chromosome formation from large or medium autosomes. This hypothesis includes dissemination of repetitive sequences and development of intercalary heterochromatic blocks in euchromatic chromosome arm followed by deletion of euchromatic regions located between them. The hypothesis is based on the findings of the Eyprepocnemis plorans specimens with autosome containing numerous intercalary repeat clusters, analysis of C-positive Bs in Eyprepocnemis plorans and Podisma sapporensis containing intercalary and terminal C-negative regions, and development of heterochromatic neo-Y chromosome in some Pamphagidae grasshoppers.

AB - B chromosomes (Bs) were described in most taxa of eukaryotes and in around 11.9% of studied Orthopteran species. In some grasshopper species, their evolution has led to many B chromosome morphotypes. We studied the Bs in nine species (Nocaracris tardus, Nocaracris cyanipes, Aeropus sibiricus, Chorthippus jacobsoni, Chorthippus apricarius, Bryodema gebleri, Asiotmethis heptapotamicus songoricus, Podisma sapporensis, and Eyprepocnemis plorans), analyzing their possible origin and further development. The studied Bs consisted of C-positive or C-positive and C-negative regions. Analyzing new data and considering current hypotheses, we suggest that Bs in grasshoppers could arise through different mechanisms and from different chromosomes of the main set. We gave our special attention to the Bs with C-negative regions and suggest a new hypothesis of B chromosome formation from large or medium autosomes. This hypothesis includes dissemination of repetitive sequences and development of intercalary heterochromatic blocks in euchromatic chromosome arm followed by deletion of euchromatic regions located between them. The hypothesis is based on the findings of the Eyprepocnemis plorans specimens with autosome containing numerous intercalary repeat clusters, analysis of C-positive Bs in Eyprepocnemis plorans and Podisma sapporensis containing intercalary and terminal C-negative regions, and development of heterochromatic neo-Y chromosome in some Pamphagidae grasshoppers.

KW - B chromosomes

KW - DNA composition

KW - Euchromatin degradation

KW - Grasshoppers

KW - Microdissected DNA probes

KW - Repeat clusters

KW - EYPREPOCNEMIS-PLORANS

KW - ABRACRIS-FLAVOLINEATA ORTHOPTERA

KW - C-BANDING PATTERNS

KW - ACRIDIDAE

KW - microdissected DNA probes

KW - grasshoppers

KW - HUMAN GENOME

KW - FISH

KW - euchromatin degradation

KW - RIBOSOMAL DNA

KW - repeat clusters

KW - GOMPHOCERUS-SIBIRICUS ORTHOPTERA

KW - A-CHROMOSOME

KW - REPETITIVE DNA

UR - http://www.scopus.com/inward/record.url?scp=85055675449&partnerID=8YFLogxK

U2 - 10.3390/genes9100509

DO - 10.3390/genes9100509

M3 - Article

C2 - 30340429

AN - SCOPUS:85055675449

VL - 9

JO - Genes

JF - Genes

SN - 2073-4425

IS - 10

M1 - 509

ER -