3H-uridine labelling patterns and chromosomal polymorphism inDrosophila subobscura: J and U chromosomes

Genetica ◽  
1984 ◽  
Vol 63 (2) ◽  
pp. 147-152 ◽  
Author(s):  
F. J. Silva
Keyword(s):  
Chromosomal Polymorphism

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 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.

scholarly journals Inversion polymorphism in some natural populations of Drosophila pseudoobscura from central Mexico

Genetika ◽  
2007 ◽  
Vol 39 (3) ◽  
pp. 343-354 ◽  
Author(s):  
Víctor Salceda ◽  
Judith Guzmán ◽  
Olga Olvera
Keyword(s):  
Relative Frequency ◽  
Polytene Chromosomes ◽  
Natural Populations ◽  
Chromosomal Polymorphism ◽  
Drosophila Pseudoobscura ◽  
Central Mexico ◽  
The Third ◽  
Grand Total ◽  
Different Populations ◽  
Single Larva

Samples of D. pseudoobscura were taken in seventeen localities in Central Mexico inside the parallels 18o - 20o N, with the purpose of determine the chromosomal polymorphism in the third of the different populations of this species. From each captured female a single larva of its offspring was taken, its salivary glands extracted and stained with a solution of aceto orcein to observe the polytene chromosomes. From these smears the corresponding karyotype of each larva was determined, keeping a record of them. With the information gathered the relative frequency of each one of the fourteen different inversions found was calculated. A grand total of 1894 third chromosomes were analyzed. The fourteen different inversions found are equivalent to a 34.1 % of the total chromosomal variation of the species. The most abundant inversions found were: TL 50.6 %, CU 27.2 5, SC 9.1 % and EP 5.5 %; the remaining ten inversions detected are in general grounds rare ones with variable relative frequencies depending on the locality. Analysis of the predominant inversions for each population was done. The presence of West-East gradients is reported, even if in cases not so well defined, since as one moves in a particular direction the ups and downs in relative frequency for the alternating pairs TL-CU; TL-SC in the western populations and TL-CU in the eastern ones were observed. The assignment of each population to a particular race was also done, and such a way we were able to recognize three different races coexisting in the area of study.

scholarly journals The pink salmon genome: uncovering the genomic consequences of a strict two-year life-cycle

2021 ◽  
Author(s):  
Kris A. Christensen ◽  
Eric B. Rondeau ◽  
Dionne Sakhrani ◽  
Carlo A. Biagi ◽  
Hollie Johnson ◽  
...  
Keyword(s):  
Pacific Salmon ◽  
Pink Salmon ◽  
Chromosomal Polymorphism ◽  
Oncorhynchus Gorbuscha ◽  
Sequencing Data ◽  
Isolated Populations ◽  
Temporal Isolation ◽  
History Of ◽  
Genome Assemblies ◽  
Salmon Fishery

Pink salmon (Oncorhynchus gorbuscha) adults are the smallest of the five Pacific salmon native to the western Pacific Ocean. Pink salmon are also the most abundant of these species and account for a large proportion of the commercial value of the salmon fishery worldwide. A strict two-year life-history of most pink salmon generates temporally isolated populations that spawn either in even-years or odd-years. To uncover the influence of this genetic isolation, reference genome assemblies were generated for each year-class and whole genome re-sequencing data was collected from salmon of both year-classes. The salmon were sampled from six Canadian rivers and one Japanese river. At multiple centromeres we identified peaks of Fst between year-classes that were millions of base-pairs long. The largest Fst peak was also associated with a million base-pair chromosomal polymorphism found in the odd-year genome near a centromere. These Fst peaks may be the result of centromere drive or a combination of reduced recombination and genetic drift, and they could influence speciation. Other regions of the genome influenced by odd-year and even-year temporal isolation and tentatively under selection were mostly associated with genes related to immune function, organ development/maintenance, and behaviour.

Sign in / Sign up

Export Citation Format

Share Document