Search results

1

C-heterochromatin and extra (B) chromosome distribution in six species of the Nabis (Heteroptera, Nabidae) with the modal male karyotype 2n = 16 + XY

100%

Grozeva S., Nokkala S.

|

vol. 51

|

issue 1-2

13-21

EN

The basic male karyotype of the six Nabis species (Heteroptera, Nabidae) is confirmed as being 2n=16+XY. The chromosomes are holokinetic while male meiosis is achiasmatic. The sex chromosomes undergo postreduction and in second metaphase show distance pairing, registered in all nabid species examined so far. Using C-banding technique for the first time in the family Nabidae, the heterochromatin was revealed on chromosomes of six species. The species showed different amount and distribution of C-heterochromatin. Only in Nabis (Dolichonabis) limbatus did the C-bands distribution make possible the identification of every chromosome pair in the karyotype. In other species, C-bands were found in some of the autosomes and the X, localized either interstitially or at telomeres. Only theYusually showed relative stability of the C-banding pattern. In four of six species, extra (B) chromosomes were observed and their behaviour in meiosis described.

2

Chromosome numbers, sex determining systems, and patterns of the C-heterochromatin distribution in 13 species of lace bugs (Heteroptera, Tingidae)

86%

Grozeva S., Nokkala S.

Folia Biologica

|

2001

|

vol. 49

|

issue 1-2

29-41

EN

The karyotypes, sex chromosome systems, and male meiotic patterns in 13 species belonging to 10 genera of the family Tingidae were studied. Data on eleven species, one subgenus, and 5 genera are presented for the first time, and the chromosome formula of Acalypta parvula is revised. Karyotypes of all species included six pairs of autosomes. Most of the species displayed an XY sex chromosome system, in four species, belonging to genera of Acalypta and Kalama, the X0 system was found. Male meiosis is chiasmatic for autosomes. Sex chromosomes are achiasmatic and undergo pre-reductional meiosis. Using C-banding technique, for the first time constitutive heterochromatin was localized on chromosomes in all the species studied. The heterochromatin was found either in telomeres or in some species in interstitial locations, evidencing that a quite substantial redistribution of chromosome material within chromosomes might occur without fragmentations or fusions. In two species, a supernumerary (B) chromosome was found. In addition, the male reproductive system of four species was examined and the number of testicular follicles was determined as two per testis.

3

Cytogenetic characterization of the trinidad endemic, Arachnocoris trinitatus Bergroth: the first data for the tribe arachnocorini (Heteroptera: Cimicomorpha: Nabidae)

72%

Kuznetsova V. G., Grozeva S., Sewlal J. N., Nokkala S.

|

2007

|

vol. 55

|

issue 1-2

17-26

EN

Cimicomorpha), the first evidence for the tribe Arachnocorini (the subfamily Nabinae), with reference to the Trinidad endemic, Arachnocoris trinitatus Bergroth, is provided. This is an attempt to gain a better insight into the evolution, systematics and within-family relationships of the family Nabidae. The studies were conducted using a number of cytogenetic techniques. The male karyotype (chromosome number and size; sex chromosome system; NOR location; C-heterochromatin amount, distribution and characterization in terms of the presence of AT-rich and GC-rich DNA), and male meiosis with particular emphasis on the behavior of the sex chromosomes in metaphase II are described. Also investigated are the male and female internal reproductive organs with special reference to the number of follicles in a testis and the number of ovarioles in an ovary. A. trinitatus was found to display a number of characters differentiating it from all hitherto studied nabid species placed in the tribe Nabini of the subfamily Nabinae, and in the tribe Prostemmatini of the subfamily Prostemmatinae. Among these characters are chromosome number 2n = 12 (10 + XY), the lowest within the family, nucleolus organizer regions (NORs) situated on the autosomes rather than on the sex chromosomes as is the case in other nabid species, and testes composed of 3 follicles but not of 7 as in other nabids. All the data obtained suggest many transformations during the evolution of A. trinitatus.

Refine search results

3 Folia Biologica

1 2007

1 2002

1 2001

3 Grozeva S.

3 Nokkala S.

1 Kuznetsova V. G.

1 Sewlal J. N.

C-heterochromatin and extra (B) chromosome distribution in six species of the Nabis (Heteroptera, Nabidae) with the modal male karyotype 2n = 16 + XY

Chromosome numbers, sex determining systems, and patterns of the C-heterochromatin distribution in 13 species of lace bugs (Heteroptera, Tingidae)

Cytogenetic characterization of the trinidad endemic, Arachnocoris trinitatus Bergroth: the first data for the tribe arachnocorini (Heteroptera: Cimicomorpha: Nabidae)