scholarly journals Karyotype Diversity, Mode, and Tempo of the Chromosomal Evolution of Attina (Formicidae: Myrmicinae: Attini): Is There an Upper Limit to Chromosome Number?

Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1084
Author(s):  
Danon Clemes Cardoso ◽  
Maykon Passos Cristiano
Keyword(s):  
Chromosome Number ◽  
Genome Size ◽  
Chromosomal Evolution ◽  
Upper Limit ◽  
Model Study ◽  
A Genome ◽  
Fungus Growing Ants ◽  
Evolutionary Paths ◽  
Limited Spectrum ◽  
Evolutionary Stasis

Ants are an important insect group that exhibits considerable diversity in chromosome numbers. Some species show only one chromosome, as in the males of the Australian bulldog ant Myrmecia croslandi, while some have as many as 60 chromosomes, as in the males of the giant Neotropical ant Dinoponera lucida. Fungus-growing ants are a diverse group in the Neotropical ant fauna, engaged in a symbiotic relationship with a basidiomycete fungus, and are widely distributed from Nearctic to Neotropical regions. Despite their importance, new chromosome counts are scarcely reported, and the marked variation in chromosome number across species has been poorly studied under phylogenetic and genome evolutionary contexts. Here, we present the results of the cytogenetic examination of fungus-farming ants and compile the cytogenetic characteristics and genome size of the species studied to date to draw insights regarding the evolutionary paths of karyotype changes and diversity. These data are coupled with a fossil-calibrated phylogenetic tree to discuss the mode and tempo of chromosomal shifting, considering whether there is an upper limit for chromosome number and genome size in ants, using fungus-farming ants as a model study. We recognize that karyotypes are generally quite variable across fungus-farming ant phylogeny, mostly between genera, and are more numerically conservative within genera. A low chromosome number, between 10 and 12 chromosomes, seems to present a notable long-term evolutionary stasis (intermediate evolutionary stasis) in fungus-farming ants. All the genome size values were inside a limited spectrum below 1 pg. Eventual departures in genome size occurred with regard to the mean of 0.38 pg, indicating that there is a genome, and likely a chromosome, number upper limit.

scholarly journals A Nearly Complete Genome of Ciona intestinalis Type A (C. robusta) Reveals the Contribution of Inversion to Chromosomal Evolution in the Genus Ciona

2019 ◽  
Vol 11 (11) ◽  
pp. 3144-3157 ◽  
Author(s):  
Yutaka Satou ◽  
Ryohei Nakamura ◽  
Deli Yu ◽  
Reiko Yoshida ◽  
Mayuko Hamada ◽  
...  
Keyword(s):  
Genome Size ◽  
Inbred Line ◽  
Genome Assembly ◽  
Ciona Intestinalis ◽  
Type A ◽  
Chromosomal Evolution ◽  
Sequence Information ◽  
A Genome ◽  
Biological Studies ◽  
Wide Range

Abstract Since its initial publication in 2002, the genome of Ciona intestinalis type A (Ciona robusta), the first genome sequence of an invertebrate chordate, has provided a valuable resource for a wide range of biological studies, including developmental biology, evolutionary biology, and neuroscience. The genome assembly was updated in 2008, and it included 68% of the sequence information in 14 pairs of chromosomes. However, a more contiguous genome is required for analyses of higher order genomic structure and of chromosomal evolution. Here, we provide a new genome assembly for an inbred line of this animal, constructed with short and long sequencing reads and Hi-C data. In this latest assembly, over 95% of the 123 Mb of sequence data was included in the chromosomes. Short sequencing reads predicted a genome size of 114–120 Mb; therefore, it is likely that the current assembly contains almost the entire genome, although this estimate of genome size was smaller than previous estimates. Remapping of the Hi-C data onto the new assembly revealed a large inversion in the genome of the inbred line. Moreover, a comparison of this genome assembly with that of Ciona savignyi, a different species in the same genus, revealed many chromosomal inversions between these two Ciona species, suggesting that such inversions have occurred frequently and have contributed to chromosomal evolution of Ciona species. Thus, the present assembly greatly improves an essential resource for genome-wide studies of ascidians.

Towards a Genome Size and Chromosome Number Database of Balkan Flora: C-Values in 343 Taxa with Novel Values for 242

2010 ◽  
Vol 3 (2) ◽  
pp. 190-213 ◽  
Author(s):  
S. Siljak-Yakovlev ◽  
F. Pustahija ◽  
E. M. Šolić ◽  
F. Bogunić ◽  
E. Muratović ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Genome Size ◽  
A Genome

scholarly journals Lineage-specific patterns of chromosome evolution are the rule not the exception in Polyneoptera insects

2020 ◽  
Vol 287 (1935) ◽  
pp. 20201388 ◽  
Author(s):  
Terrence Sylvester ◽  
Carl E. Hjelmen ◽  
Shawn J. Hanrahan ◽  
Paul A. Lenhart ◽  
J. Spencer Johnston ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Genome Size ◽  
Sex Chromosomes ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Genome Structure ◽  
Rates Of Evolution ◽  
A Genome ◽  
Sex Chromosome System ◽  
Insect Group

The structure of a genome can be described at its simplest by the number of chromosomes and the sex chromosome system it contains. Despite over a century of study, the evolution of genome structure on this scale remains recalcitrant to broad generalizations that can be applied across clades. To address this issue, we have assembled a dataset of 823 karyotypes from the insect group Polyneoptera. This group contains orders with a range of variations in chromosome number, and offer the opportunity to explore the possible causes of these differences. We have analysed these data using both phylogenetic and taxonomic approaches. Our analysis allows us to assess the importance of rates of evolution, phylogenetic history, sex chromosome systems, parthenogenesis and genome size on variation in chromosome number within clades. We find that fusions play a key role in the origin of new sex chromosomes, and that orders exhibit striking differences in rates of fusions, fissions and polyploidy. Our results suggest that the difficulty in finding consistent rules that govern evolution at this scale may be due to the presence of many interacting forces that can lead to variation among groups.

scholarly journals Genome Size and Chromosome Number Evolution in Korean Iris L. Species (Iridaceae Juss.)

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1284 ◽  
Author(s):  
Bokyung Choi ◽  
Hanna Weiss-Schneeweiss ◽  
Eva M. Temsch ◽  
Soonku So ◽  
Hyeon-Ho Myeong ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Genome Size ◽  
Chromosome Numbers ◽  
Size Variation ◽  
Chromosomal Evolution ◽  
Genome Size Variation ◽  
Molecular Cytogenetic ◽  
Chromosome Number Evolution ◽  
Phylogenetic Framework ◽  
Phylogenomic Analyses

Chromosome numbers, karyotypes, and genome sizes of 14 Iris L. (Iridaceae Juss.) species in Korea and their closely related taxon, Sisyrinchium rosulatum, are presented and analyzed in a phylogenetic framework. To date, understanding the chromosomal evolution of Korean irises has been hampered by their high chromosome numbers. Here, we report analyses of chromosome numbers and karyotypes obtained via classic Feulgen staining and genome sizes measured using flow cytometry in Korean irises. More than a two-fold variation in chromosome numbers (2n = 22 to 2n = 50) and over a three-fold genome size variation (2.39 pg to 7.86 pg/1 C) suggest the putative polyploid and/or dysploid origin of some taxa. Our study demonstrates that the patterns of genome size variation and chromosome number changes in Korean irises do not correlate with the phylogenetic relationships and could have been affected by different evolutionary processes involving polyploidy or dysploidy. This study presents the first comprehensive chromosomal and genome size data for Korean Iris species. Further studies involving molecular cytogenetic and phylogenomic analyses are needed to interpret the mechanisms involved in the origin of chromosomal variation in the Iris.

scholarly journals DNA Genome Size Affects the Stability of the Adenovirus Virion

2008 ◽  
Vol 83 (4) ◽  
pp. 2025-2028 ◽  
Author(s):  
Adam C. Smith ◽  
Kathy L. Poulin ◽  
Robin J. Parks
Keyword(s):  
Genome Size ◽  
Critical Role ◽  
Heat Stability ◽  
Helper Virus ◽  
Heat Inactivation ◽  
Similar Relationship ◽  
Viral Dna ◽  
A Genome ◽  
The Stability ◽  
Replication Defective Adenovirus

ABSTRACT Replication-defective adenovirus (Ad) vectors can vary considerably in genome length, but whether this affects virion stability has not been investigated. Helper-dependent Ad vectors with a genome size of ∼30 kb were 100-fold more sensitive to heat inactivation than their parental helper virus (>36 kb), and increasing the genome size of the vector significantly improved heat stability. A similar relationship between genome size and stability existed for Ad with early region 1 deleted. Loss of infectivity was due to release of vertex proteins, followed by disintegration of the capsid. Thus, not only does the viral DNA encode all of the heritable information essential for virus replication, it also plays a critical role in maintaining capsid strength and integrity.

scholarly journals Genome size versus geographic range size in birds

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10868
Author(s):  
Beata Grzywacz ◽  
Piotr Skórka
Keyword(s):  
Natural Selection ◽  
Chromosome Number ◽  
Genome Size ◽  
Body Mass ◽  
Generalized Least Squares ◽  
Geographic Range ◽  
Range Size ◽  
Geographic Ranges ◽  
Brain Mass ◽  
Terrestrial Vertebrates

Why do some species occur in small, restricted areas, while others are distributed globally? Environmental heterogeneity increases with area and so does the number of species. Hence, diverse biotic and abiotic conditions across large ranges may lead to specific adaptations that are often linked to a species’ genome size and chromosome number. Therefore, a positive association between genome size and geographic range is anticipated. Moreover, high cognitive ability in organisms would be favored by natural selection to cope with the dynamic conditions within large geographic ranges. Here, we tested these hypotheses in birds—the most mobile terrestrial vertebrates—and accounted for the effects of various confounding variables, such as body mass, relative brain mass, and geographic latitude. Using phylogenetic generalized least squares and phylogenetic confirmatory path analysis, we demonstrated that range size is positively associated with bird genome size but probably not with chromosome number. Moreover, relative brain mass had no effect on range size, whereas body mass had a possible weak and negative effect, and range size was larger at higher geographic latitudes. However, our models did not fully explain the overall variation in range size. Hence, natural selection may impose larger genomes in birds with larger geographic ranges, although there may be additional explanations for this phenomenon.

Psidium guajava L.: taxonomy, relatives and possible origin.

2021 ◽  
pp. 1-21
Author(s):  
Leslie R. Landrum
Keyword(s):  
Chromosome Number ◽  
Genome Size ◽  
Morphological Characteristics ◽  
Psidium Guajava ◽  
Medicinal Uses ◽  
Species Complexes

Abstract This chapter focuses on the taxonomy and geography of guava (Psidium guajava). Information is given on geography, morphological characteristics, chromosome number and genome size, phytochemistry and medicinal uses, closest relatives, and keys to species complexes.

A new species of Acianthera (Pleurothallidinae, Orchidaceae) from Brazil

Phytotaxa ◽  
2019 ◽  
Vol 402 (1) ◽  
pp. 29
Author(s):  
JAN PONERT ◽  
ZUZANA CHUMOVÁ ◽  
TEREZIE MANDÁKOVÁ ◽  
PAVEL TRÁVNÍČEK
Keyword(s):  
New Species ◽  
Chromosome Number ◽  
Molecular Phylogeny ◽  
Genome Size ◽  
Size Estimation ◽  
Abaxial Side ◽  
Phylogenetic Placement ◽  
A New Species ◽  
Half Length

Acianthera sudae is newly described based on cultivated material from Brazil. It belongs to section Cryptophoranthae and differs from all others in this group by the larger flowers and sepals fused apically for more than half length, and a green-brown abaxial side of sepals with purple dots. Chromosome number (2n = 40) and genome size estimation (1C-value = 1.18 pg) is provided and its phylogenetic placement under the genus is supported with reconstruction of a molecular phylogeny using nuclear ribosomal ITS.

scholarly journals Highly Contiguous Nanopore Genome Assembly of Chlamydomonas reinhardtii CC-1690

2020 ◽  
Vol 9 (37) ◽  
Author(s):  
Samuel O’Donnell ◽  
Frederic Chaux ◽  
Gilles Fischer
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Genome Size ◽  
Genome Assembly ◽  
Reference Genome ◽  
De Novo ◽  
Content Type ◽  
Oxford Nanopore ◽  
A Genome ◽  
Reference Quality

ABSTRACT The current Chlamydomonas reinhardtii reference genome remains fragmented due to gaps stemming from large repetitive regions. To overcome the vast majority of these gaps, publicly available Oxford Nanopore Technology data were used to create a new reference-quality de novo genome assembly containing only 21 contigs, 30/34 telomeric ends, and a genome size of 111 Mb.

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