Genotypic control of chromosome form and behaviour

1961 ◽  
Vol 27 (2) ◽  
pp. 288-318 ◽  
Author(s):  
H. Rees
Keyword(s):  
Chromosome Form ◽  
Genotypic Control

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 Genotypic Control of Chromosome Size

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

THE STRUCTURE AND DEVELOPMENT OF THE CHROMOSOME SPIRALS IN MICROSPORES OF TRILLIUM

1942 ◽  
Vol 20c (4) ◽  
pp. 257-266 ◽  
Author(s):  
A. H. Sparrow
Keyword(s):  
Meiotic Prophase ◽  
Spiral Structure ◽  
Chromosome Form ◽  
Single Coil ◽  
Contraction Ratio

The structure and development of somatic spirals in microspore chromosomes of Trillium have been investigated. The chromonemata in each metaphase chromatid and each anaphase chromosome form a large-gyred, hollow spiral. This spiral develops gradually during prophase by an increase in gyre diameter and a decrease in gyre number and in chromatid length. Its development is associated with the elimination not the production of chromatid relational coiling. At later stages an irregular waviness or "minor" somatic spiral is visible along its "major" gyres in which reversals of direction can also be discerned. Where the spiral can be seen to be double-stranded it is plectonemic (as early as mid-prophase).The prophase to metaphase chromatid contraction ratio is not less than 6:1. Mean chromonema length increases from 650 ± 17.2 at metaphase to 977 ± 28.3 at anaphase. This latter length is approximately that estimated for early meiotic prophase. Chromosome volume also increases (about twofold) during the interval between metaphase and anaphase. Mean chromonema length and gyre number in microspore anaphase chromosomes are more than twice as great as those of meiotic anaphase chromosomes. Since the chromosomes at these stages are of approximately the same mean length the gyres of the somatic spiral are thus more tightly "packed".In Trillium, microspore anaphase chromosomes are considered to be of essentially the same spiral structure as meiotic second division chromosomes, i.e., a single coil (but not single-stranded), rather than two or more independently coiled chromatids. The process of reducing this plectonemic spiral into parallel, freely-separable chromatids begins in one prophase as a reduction in gyre number and continues as relational uncoiling in the next. Paradoxically, therefore, a spiralization cycle such as that described above can be interpreted as an uncoiling process in which successive cycles overlap in prophase.

scholarly journals Boundaries of loop domains (insulators): Determinants of chromosome form and function in multicellular eukaryotes

BioEssays ◽  
2017 ◽  
Vol 39 (3) ◽  
pp. 1600233 ◽  
Author(s):  
Darya Chetverina ◽  
Miki Fujioka ◽  
Maksim Erokhin ◽  
Pavel Georgiev ◽  
James B. Jaynes ◽  
...  
Keyword(s):  
Chromosome Form ◽  
Form And Function ◽  
And Function ◽  
Loop Domains

scholarly journals Genotypic control of chromosome behaviour in rye

Heredity ◽  
1955 ◽  
Vol 9 (1) ◽  
pp. 93-116 ◽  
Author(s):  
Hubert Rees
Keyword(s):  
Chromosome Behaviour ◽  
Genotypic Control

Variation in cone morphology and seed characters in Pinus strobus in Quebec

1995 ◽  
Vol 73 (2) ◽  
pp. 262-271 ◽  
Author(s):  
Jean Beaulieu ◽  
Jean-Pierre Simon
Keyword(s):  
Natural Populations ◽  
Pinus Strobus ◽  
White Pine ◽  
Ottawa River ◽  
River Region ◽  
Natural Range ◽  
Anticosti Island ◽  
Genotypic Control ◽  
Two Populations ◽  
Cone Scale

To investigate the patterns of variation in white pine (Pinus strobus L.), 10 natural populations from Quebec were compared using the phenotypic variation of cone and seed traits. Eight characters were measured on 10 cones collected from 30 trees in each of the 10 sampled populations. Four populations were from the Ottawa River region and four from the St. Lawrence Lowlands region, while two populations were at the margin of the natural range of the species in Quebec, from the Abitibi region and Anticosti Island. Significant differences among populations were detected for each character. Estimates of repeatability of these traits were relatively high, suggesting substantial genotypic control over them. These estimates were consistent from population to population. Results of multivariate analyses suggest that populations from the Ottawa River region are similar to those from the St. Lawrence region, with populations from these regions diverging only in cone scale length. However, populations from the St. Lawrence region were more distinct from each other than those from the Ottawa River region. The population from Abitibi deviates considerably from the other populations, suggesting habitat-selection pressures acting at the margin of the natural range of the species under continental conditions. Finally, no general geographical trend was detected in the observed variation. Key words: white pine, morphology, cone, seed, variation.

scholarly journals Genotypic control of chromosome behaviour in rye

Heredity ◽  
1964 ◽  
Vol 19 (3) ◽  
pp. 357-367 ◽  
Author(s):  
S Sun ◽  
H Rees
Keyword(s):  
Chromosome Behaviour ◽  
Genotypic Control
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