Origin of the complex karyotype of the polyploid parthenogenetic grasshopper Saga pedo (Orthoptera: Tettigoniidae)

Title:

Origin of the complex karyotype of the polyploid parthenogenetic grasshopper Saga pedo (Orthoptera: Tettigoniidae)

Creator:

Dutrillaux, Anne Marie, Lemonnier-Darcemont, Michèle, Darcemont, Christian , Krpač, Vladimír , Fouchet , Pierre , and Dutrillaux, Bernard

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:fbece446-a8c0-4790-8bc7-66532cae0d98
uuid:fbece446-a8c0-4790-8bc7-66532cae0d98

Subject:

Tettigoniidae, Saga pedo, chromosomes, DNA content, karyotype evolution, and pentaploidy

Type:

article, model:article, and TEXT

Description:

Karyotypes of the polyploid parthenogenetic species Saga pedo from four localities in France and the Republic of Macedonia were constructed and compared. All these karyotypes consist of 70 chromosomes, which is more than twice that in other species of the genus. The chromosomes differ from each other, making the matching of homologues difficult. Karyotypes of French specimens are similar, except for differences in the heterochromatin. Compared to that of the Macedonian specimens those from French specimens differ by the shortening of a single chromosome. The difficulty experienced in identifying tetrads and even pairs of chromosomes indicates that either many chromosome rearrangements have occurred since the polyploidisation event(s) or that the addition of quite different genomes is the cause. On the other hand, that the karyotypes are similar indicates a common origin of both the Macedonian and French populations. Thus, most chromosome changes preceded the separation from their common ancestor. Both the DNA content and chromosome analyses suggest that the S. pedo karyotype is pentaploid and not tetraploid as previously proposed. This odd ploidy number rules out the hypothesis that it could only have originated by endoreduplication. It is more likely that it originated by the association of five copies of the 14,X haploid karyotype, which exists in the gametes of the closely related species, S. campbelli and S. rammei (male / female 2n = 27, X / 28, XX). Fertilization of a parthenogenetic 56, XXXX female by a 14, X spermatozoa could have resulted in the last increase in ploidy.

Language:

English

Rights:

http://creativecommons.org/publicdomain/mark/1.0/
policy:public

Source:

European Journal of Entomology | 2009 Volume:106 | Number:4

Harvested from:

CDK

Metadata only:

false