Sources of Chromosomal Polymorphism of Microsporocytes in Species of Lilium L. and Allium L.: Cytomixis, Extra Chromosomes, and Chromatin Diminution

2021 ◽  
Vol 55 (2) ◽  
pp. 107-116
Author(s):  
E. A. Kravets ◽  
S. H. Plohovskaya ◽  
I. I. Horyunova ◽  
A. I. Yemets ◽  
Ya. B. Blume
Keyword(s):  
Chromosomal Polymorphism ◽  
Chromatin Diminution

CHROMOSOMAL POLYMORPHISM IN DROSOPHILA EURONOTUS

Genetics ◽  
1964 ◽  
Vol 49 (4) ◽  
pp. 669-687
Author(s):  
Harrison D Stalker
Keyword(s):  
Chromosomal Polymorphism

Chromosomal Patterns of Microsatellite Variability Contrast Sharply in African and Non-African Populations of Drosophila melanogaster

Genetics ◽  
2002 ◽  
Vol 160 (1) ◽  
pp. 247-256
Author(s):  
M Kauer ◽  
B Zangerl ◽  
D Dieringer ◽  
C Schlötterer
Keyword(s):  
Chromosomal Polymorphism ◽  
Background Selection ◽  
Selective Sweeps ◽  
X Chromosomes ◽  
Evolutionary Forces ◽  
Relative Contribution ◽  
African Populations ◽  
Neutral Variation ◽  
Colonization Process ◽  
The Subject

Abstract Levels of neutral variation are influenced by background selection and hitchhiking. The relative contribution of these evolutionary forces to the distribution of neutral variation is still the subject of ongoing debates. Using 133 microsatellites, we determined levels of variability on X chromosomes and autosomes in African and non-African D. melanogaster populations. In the ancestral African populations microsatellite variability was higher on X chromosomes than on autosomes. In non-African populations X-linked polymorphism is significantly more reduced than autosomal variation. In non-African populations we observed a significant positive correlation between X chromosomal polymorphism and recombination rate. These results are consistent with the interpretation that background selection shapes levels of neutral variability in the ancestral populations, while the pattern in derived populations is determined by multiple selective sweeps during the colonization process. Further research, however, is required to investigate the influence of inversion polymorphisms and unequal sex ratios.

scholarly journals Development and analysis of a germline BAC resource for the sea lamprey, a vertebrate that undergoes substantial chromatin diminution

Chromosoma ◽  
2010 ◽  
Vol 119 (4) ◽  
pp. 381-389 ◽  
Author(s):  
Jeramiah J. Smith ◽  
Andrew B. Stuart ◽  
Tatjana Sauka-Spengler ◽  
Sandra W. Clifton ◽  
Chris T. Amemiya
Keyword(s):  
Sea Lamprey ◽  
Chromatin Diminution

scholarly journals CHROMOSOMAL POLYMORPHISM IN THE SU GENOME COMPLEX OF POLYPLOID TRILLIUMS

1974 ◽  
Vol 49 (6) ◽  
pp. 413-424 ◽  
Author(s):  
TUTOMU HAGA ◽  
HIROSHI WATANABE ◽  
AKINORI UCHINO
Keyword(s):  
Chromosomal Polymorphism

ADAPTIVE CHROMOSOMAL POLYMORPHISM INDROSOPHILA MELANICA

Evolution ◽  
1973 ◽  
Vol 27 (3) ◽  
pp. 486-494 ◽  
Author(s):  
John Tonzetich ◽  
Calvin L. Ward
Keyword(s):  
Chromosomal Polymorphism

CHROMOSOMAL POLYMORPHISM AND INTER-RELATIONSHIPS IN PISSODES WEEVILS: ADDITIONAL CYTOGENETIC EVIDENCE OF SYNONYMY

1973 ◽  
Vol 15 (1) ◽  
pp. 83-100 ◽  
Author(s):  
S. G. Smith
Keyword(s):  
Chromosomal Polymorphism ◽  
Valid Species ◽  
Cytogenetic Evidence

Chromosome comparison and crossability tests compel relegating 6 of 10 Hopkins' Pissodes taxa to synonymy, namely, utahensis with similis Hopk., nigrae and alascensis with rotundatus Lec., fraseri and piperi with dubius Rand., and curriei with affinis Rand. Two, dubius and rotundatus, and possibly a third, affinis, of the four valid species revealed meiotic markers of semi-incompatibility not previously encountered; presumably, as in the strobi complex, the fourth, similis, is merely devoid of the necessary chromosomal diagnostic.

Genome size in cyclopoid copepods (Copepoda: Cyclopoida): chromatin diminution as a hypothesized mechanism of evolutionary constraint

2021 ◽  
Vol 41 (3) ◽  
Author(s):  
Emilly Schutt ◽  
Maria Hołyńska ◽  
Grace A Wyngaard
Keyword(s):  
Genome Size ◽  
Life Histories ◽  
Nuclear Dna ◽  
Cell Lineage ◽  
Fundamental Property ◽  
Nuclear Dna Content ◽  
Evolutionary Constraint ◽  
Chromatin Diminution ◽  
Somatic Genome ◽  
Copepoda Cyclopoida

Abstract Genome size is a fundamental property of organisms that impacts their molecular evolution and life histories. The hypothesis that somatic genome sizes in copepods in the order Cyclopoida are small and evolutionary constrained relative to those in the order Calanoida was proposed 15 years ago. Since then, the number of estimates has almost doubled and the taxon sampling has broadened. Here we add 14 new estimates from eight genera of freshwater cyclopoids that vary from 0.2 to 6.6 pg of DNA per nucleus in the soma; all except one are 2.0 pg DNA per nucleus or smaller. This new sample adds to the pattern of genome size in copepods and is remarkably similar to the distribution on which the original hypothesis was based, as well as those of subsequently published estimates. Embryonic chromatin diminution, during which large portions of DNA are excised from the presomatic cell lineage, is reported in Paracyclops affinis (G.O. Sars, 1863). This diminution results in a somatic genome that is one half the size of the germline genome. When the sizes of the germline genomes carried in presomatic cells of cyclopoid species that possess chromatin diminution are considered, the prediminuted germline genome sizes of cyclopoid embryos overlap with the distribution of calanoid somatic genome sizes, supporting the hypothesis that chromatin diminution has functioned as a mechanism to constrain somatic nuclear DNA content in cyclopoid copepods. Geographically based variation in genome size among populations is also reviewed.

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