scholarly journals Genotypic Control of Chromosome Size

Nature ◽  
1936 ◽  
Vol 138 (3488) ◽  
pp. 402-402 ◽  
Author(s):  
PERCY T. THOMAS
Keyword(s):  
Chromosome Size ◽  
Genotypic Control

Genotypic control of centromere positions of parental genomes in Hordeum × Secale hybrid metaphases

1987 ◽  
Vol 87 (2) ◽  
pp. 291-304
Author(s):  
TRUDE SCHWARZACHER-ROBINSON ◽  
R. A. FINCH ◽  
J. B. SMITH ◽  
M. D. BENNETT
Keyword(s):  
Three Dimensional ◽  
Metaphase Plate ◽  
Peripheral Region ◽  
Root Tip ◽  
Chromosome Size ◽  
Pooled Data ◽  
Large Size ◽  
Tip Cells ◽  
Genotypic Control ◽  
Root Tip Cells

The spatial disposition at metaphase of centromeres from Hordeum and Secale in root tip cells of H. chilense × S. africanum is described and compared with corresponding results for H. vulgare × S. africanum obtained previously. In both of these F1 sexual hybrids (2n = 2x = 14) each of the seven chromosome types from Secale was easily distinguished by its large size from any of the seven from Hordeum. In H. chilense × S. africanum, centromeres of Secale chromosomes tended to be nearer the centre of the metaphase plate than did centromeres of Hordeum chromosomes in both squash preparations seen by light microscopy and unsquashed cells examined using electron microscope three-dimensional serial thin section reconstructions. This difference was significant in some individual cells, and highly significant for pooled data for reconstructed cells and separately for squashed metaphases. In no cell were Hordeum centromeres on average significantly nearer the centre of the metaphase plate than Secale centromeres. These results agreed with those previously obtained for H. vulgare × S. africanum in that: (1) centromeres of the two parental haploid sets tended to be spatially separate; and (2) centromeres from one particular parent usually tended to be in the peripheral region of the metaphase plate that surrounded the central region containing the centromeres from the other parent. However, these results contrasted completely with those obtained previously in that Secale centromeres tended to be more central than Hordeum centromeres in H. chilense × S. africanum, but more peripheral than Hordeum centromeres in H. vulgare × S. africanum. As centromeres of the parental set with the larger chromosomes (i.e. Secale) can be either inside, or outside, centromeres from the parental genome with the smaller chromosomes (i.e. Hordeum), then clearly, a tendency for a concentric separation of parental genomes is not a packing phenomenon determined by chromosome size perse, but is presumably under genotypic control.

Chromosome size-dependent control of meiotic recombination

Science ◽  
1992 ◽  
Vol 256 (5054) ◽  
pp. 228-232 ◽  
Author(s):  
D. Kaback ◽  
V Guacci ◽  
D Barber ◽  
J. Mahon
Keyword(s):  
Meiotic Recombination ◽  
Chromosome Size ◽  
Size Dependent

scholarly journals Distribution of Multivalents and Genotypic Control of Chromosome Pairing in Setcreasea Species and Hybrids

CYTOLOGIA ◽  
1971 ◽  
Vol 36 (2) ◽  
pp. 309-320 ◽  
Author(s):  
K. L. Mehra ◽  
P. R. Sreenath ◽  
S. A. Faruqi
Keyword(s):  
Chromosome Pairing ◽  
Genotypic Control

scholarly journals Patterns of genome size variation in snapping shrimp

Genome ◽  
2016 ◽  
Vol 59 (6) ◽  
pp. 393-402 ◽  
Author(s):  
Nicholas W. Jeffery ◽  
Kristin Hultgren ◽  
Solomon Tin Chi Chak ◽  
T. Ryan Gregory ◽  
Dustin R. Rubenstein
Keyword(s):  
Genome Size ◽  
Phylogenetic Signal ◽  
Size Variation ◽  
Diverse Group ◽  
Chromosome Size ◽  
Genome Size Variation ◽  
Large Genome ◽  
Large Genome Size ◽  
Single Genus ◽  
Geographic Regions

Although crustaceans vary extensively in genome size, little is known about how genome size may affect the ecology and evolution of species in this diverse group, in part due to the lack of large genome size datasets. Here we investigate interspecific, intraspecific, and intracolony variation in genome size in 39 species of Synalpheus shrimps, representing one of the largest genome size datasets for a single genus within crustaceans. We find that genome size ranges approximately 4-fold across Synalpheus with little phylogenetic signal, and is not related to body size. In a subset of these species, genome size is related to chromosome size, but not to chromosome number, suggesting that despite large genomes, these species are not polyploid. Interestingly, there appears to be 35% intraspecific genome size variation in Synalpheus idios among geographic regions, and up to 30% variation in Synalpheus duffyi genome size within the same colony.

Chromatin Diminution in Cyclops kolensis Lill. (Copepoda, Crustacea) as a Radical Way to Inactivate Redundant Genome in Somatic Cells

2018 ◽  
Vol 156 (3) ◽  
pp. 165-172 ◽  
Author(s):  
Andrey K. Grishanin ◽  
Maxim V. Zagoskin
Keyword(s):  
Chromosome Number ◽  
Repetitive Sequences ◽  
Early Embryogenesis ◽  
Chromosome Size ◽  
Chromatin Diminution ◽  
Elimination Process ◽  
Dna Elimination ◽  
Molecular Studies ◽  
Cyclops Kolensis

Chromatin diminution (CD) is a phenomenon of programmed DNA elimination which takes place in early embryogenesis in some eukaryotes. The mechanism and biological role of CD remain largely unknown. During CD in the freshwater copepod Cyclops kolensis, the genome of cells of the somatic lineage is reorganized and reduced in size by more than 90% without affecting the genome of germline cells. Although the diploid chromosome number is unchanged, chromosome size is dramatically reduced by CD. The eliminated DNA consists primarily of repetitive sequences and localizes within granules during the elimination process. In this review, we provide an overview of CD in C. kolensis including both cytological and molecular studies.

Natural and Induced Changes in Chromosome Size and Mass in Meristems

Nature ◽  
1967 ◽  
Vol 215 (5096) ◽  
pp. 93-94 ◽  
Author(s):  
M. D. BENNETT ◽  
H. REES
Keyword(s):  
Chromosome Size ◽  
Induced Changes

The Genome Size of Some Species of Hyalomma Ticks from Turkish Thrace 

2018 ◽  
Vol 23 (11) ◽  
pp. 2122 ◽  
Author(s):  
Nadim Yılmazer
Keyword(s):  
Genome Size ◽  
X Chromosome ◽  
Tick Species ◽  
Animal Health ◽  
Chromosome Size ◽  
Diploid Genome ◽  
Flow Cytometric ◽  
Determination System ◽  
Sex Determination System ◽  
First Time

Hyalomma scupense, H. excavatum and H. marginatum are globally important tick species, as well as in Turkey, both in terms of human and animal health. The genome sizes of these tick species were determined in this study for the first time. From flow cytometric measurements, diploid genome sizes of female and male H. scupense were found to be 2.13 pg and 1.75 pg, respectively, while H. excavatum were 2.21 pg and 1.94 pg, and H. marginatum were 2.48 pg and 1.98 pg, respectively. Differences in diploid genome size indicate X chromosome size of females and males in these ticks because they have an XX:XO sex determination system. Thus, it was estimated that the X chromosome of H. scupense, H. excavatum, and H. marginatum may be composed of as much as 0.38 pg, 0.27 pg, and 0.50 pg of DNA, respectively. These findings indicate suitability of these three species for genome sequencing due to the relatively small size of their genomes compared with other tick species.

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