Heterochromatin heteromorphism in Holhymenia rubiginosa (Heteroptera: Coreidae)

Abstract

Abstract.Heterochromatin is one of the most dynamic components in the genome of species. Previous studies on the heterochromatin content and distribution in Heteroptera (insects with holokinetic chromosomes) have shown that the species belonging to the family Coreidae are interesting model organisms since they show very diverse C bands patterns. In the present work, we analyzed the C-band pattern in individuals of Holhymenia rubiginosa from different populations collected in different years. This species has the diploid karyotype 2n = 27/28 = 24 + 2m + X0/XX (male/female). C-bands are terminally, subterminally or interstitially located on 10-17 chromosomes and a remarkable heterochromatin heteromorphism is observed in the meiotic bivalents: in the presence/absence of bands, in the size of bands and number of bands. A heteromorphism is also inferred in the number of ribosomal genes from the difference in the fluorescent in situ hybridization signals between NOR-homologues. Chiasmata are generally located opposite to conspicuous C-bands, but in some bivalents chiasmata are also observed in close proximity to C-bands. Considering the striking variation in heterochromatin content between individuals and populations it is suggested that heterochromatin should be selectively neutral in H. rubiginosa.

Description of the pre-reductional sex chromosome during male meiosis of Pachylis laticornis (Heteroptera: Coreidae)

“…This karyotype followed the pattern described for species of the family Coreidae (a pair of m-chromosomes and sex chromosomal system of the type X0) (Ueshima, 1979;Grozeva and Nokkala, 1996;Bressa et al, 2008).…”

“…This family has a X0/XX sex chromosome system for males and females, a pair of m-chromosomes, and a diploid chromosome number ranging from 2n = 13 (10A + 2m + X0) to 2n = 27 (24A + 2m + X0), with 2n = 21 (18A + 2m + X0) being the most common (Bressa et al, 2008).…”

Physical mapping of 18S rDNA and heterochromatin in species of family Lygaeidae (Hemiptera: Heteroptera)

“…This heteromorphism has already been reported in other species of Heteroptera, including Holhymenia rubiginosa (Bressa et al, 2008). In Ochrimnus sagax, although the CMA 3 + /DAPI -blocks have also been observed on the first pair of autosomal chromosomes, they were different from those found in Oncopeltus femoralis, since their positioning was coincident with the nucleolar constriction and in a region closer to the telomere.…”

“…In many cases, only 1 GC-rich heterochromatic block (interstitial or terminal) is recognized, which is often associated with the nucleolus organizer region (NOR; Camacho et al, 1985;Papeschi et al, 2003;Grozeva et al, 2004). Reports of interstitial heterochromatic blocks scattered throughout most autosomes are scarce and restricted to the family Curiae (Holhymenia rubiginosa and Spartocera batatas) (Fabricius, 1798) (Franco et al, 2006;Bressa et al, 2008). In the family Lygaeidae, studies on the heterochromatic location are limited to the genus Dieuches (Eyles, 1973), in which the 3 species analyzed showed AT-rich heterochromatic blocks already described in Heteroptera (Kaur et al, 2010).…”

Karyotype characterization of planthopper species Hysteropterum albaceticum Dlabola, 1983 and Agalmatium bilobum (Fieber, 1877) (Homoptera: Auchenorrhyncha: Issidae) using AgNOR-, C- and DAPI/CMA3 -banding techniques

“…In recent years however an increasing quantity of such data have appeared and shown that holokinetic chromosomes can display a great deal of C-heterochromatin (Blackman, 1976(Blackman, , 1990Kuznetsova et al 1997;Maryańska-Nadachowska, 1999;Vanzela et al, 2000;Grozeva, Nokkala, 2001;Golub et al, 2004;Angus et al, 2004;Pérez et al, 2005;Franco et al, 2006;Bressa et al, 2008;Maryańska-Nadachowska et al, 2008). The species can diverge considerably in this pattern: some display a lot of C-heterochromatin; some show prominent C-bands of different size in separate chromosomes; and in other species C-heterochromatin appeared to avoid detection due to its presence in small or minute amounts.…”