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Karyotype evolution of spiders with holokinetic chromosomes (Dysderoidea)

Thakur, Shefali (2017) MOBY01 20162
Degree Projects in Molecular Biology
Abstract
The superfamily Dysderoidea, a species-rich clade of haplogyne araneomorph spiders encompassing members that are all expected to exhibit holokinetic chromosome structure, is cytogenetically explored for this thesis. Holokinetic chromosomes lack primary constriction and centromere. In contrast to standard chromosomes, kinetochore covers most of chromosome surface of the holokinetic chromosomes. Holokinetic chromosomes arose multiple times from standard chromosomes during evolution of animals, plants, and protists. Due to specific structure, they are extremely tolerant towards chromosomal fusions and fissions. This has major implication on karyotype evolution of Dysderoidea and diverse diploid numbers are seen in the superfamily. Species... (More)
The superfamily Dysderoidea, a species-rich clade of haplogyne araneomorph spiders encompassing members that are all expected to exhibit holokinetic chromosome structure, is cytogenetically explored for this thesis. Holokinetic chromosomes lack primary constriction and centromere. In contrast to standard chromosomes, kinetochore covers most of chromosome surface of the holokinetic chromosomes. Holokinetic chromosomes arose multiple times from standard chromosomes during evolution of animals, plants, and protists. Due to specific structure, they are extremely tolerant towards chromosomal fusions and fissions. This has major implication on karyotype evolution of Dysderoidea and diverse diploid numbers are seen in the superfamily. Species inspected belong to families Dysderidae, Oonopidae, and Orsolobidae. This work represents a cross-section through these clades. Most of species included are karyotypically examined for the first time and karyotypes for others are revised. (Less)
Popular Abstract
Highly diverse diploid numbers are reported in the genus Dysdera, particulary in Dysdera longirostris from different geographical locations. These clades exhibit very conserved karyotypes with low diploid numbers. Clades examined for the first time (families Oonopidae and Orsolobidae as well as subfamilies Harpacteinae and Rhodinae; Dysderidae) seem to exhibit karyotypes with low diploid numbers. Tedia abdominalis (Dysderidae) exhibits the highest diploid number for haplogyne spiders (2n♂ = 51). Sex chromosome systems of the X0, X1..Xn, and XY types are reported in the superfamily. Multiple sex chromosome systems are common. Holokinetic chromosomes display a number of curious behaviors at mitosis and meiosis, including inverted meiosis.... (More)
Highly diverse diploid numbers are reported in the genus Dysdera, particulary in Dysdera longirostris from different geographical locations. These clades exhibit very conserved karyotypes with low diploid numbers. Clades examined for the first time (families Oonopidae and Orsolobidae as well as subfamilies Harpacteinae and Rhodinae; Dysderidae) seem to exhibit karyotypes with low diploid numbers. Tedia abdominalis (Dysderidae) exhibits the highest diploid number for haplogyne spiders (2n♂ = 51). Sex chromosome systems of the X0, X1..Xn, and XY types are reported in the superfamily. Multiple sex chromosome systems are common. Holokinetic chromosomes display a number of curious behaviors at mitosis and meiosis, including inverted meiosis. Inverted meiosis has occured in the sex chromosome and autosome trivalents of some dysderids. Mechanisms of autosomal and sex chromosome evolution in the superfamily includes chromosomal rearrangements, especially fissions and fusions. The ancestral karyotype for the superfamily is most likely composed of a low diploid number.

Advisor: Dr. Jiří Král
Degree Project in Molecular Biology 30 credits 2016
Department of Biology, Lund University (Less)
Please use this url to cite or link to this publication:
author
Thakur, Shefali
supervisor
organization
course
MOBY01 20162
year
type
H1 - Master's Degree (One Year)
subject
language
English
id
8904963
date added to LUP
2017-03-22 11:25:40
date last changed
2017-03-22 11:25:40
@misc{8904963,
  abstract     = {The superfamily Dysderoidea, a species-rich clade of haplogyne araneomorph spiders encompassing members that are all expected to exhibit holokinetic chromosome structure, is cytogenetically explored for this thesis. Holokinetic chromosomes lack primary constriction and centromere. In contrast to standard chromosomes, kinetochore covers most of chromosome surface of the holokinetic chromosomes. Holokinetic chromosomes arose multiple times from standard chromosomes during evolution of animals, plants, and protists. Due to specific structure, they are extremely tolerant towards chromosomal fusions and fissions. This has major implication on karyotype evolution of Dysderoidea and diverse diploid numbers are seen in the superfamily. Species inspected belong to families Dysderidae, Oonopidae, and Orsolobidae. This work represents a cross-section through these clades. Most of species included are karyotypically examined for the first time and karyotypes for others are revised.},
  author       = {Thakur, Shefali},
  language     = {eng},
  note         = {Student Paper},
  title        = {Karyotype evolution of spiders with holokinetic chromosomes (Dysderoidea)},
  year         = {2017},
}