scholarly journals Genome size and repetitive sequences are driven by artificial selection on the length of the vegetative cycle in maize landraces from Northeastern Argentina

Rodriguésia ◽  
2021 ◽  
Vol 72 ◽  
Author(s):  
María Florencia Realini ◽  
Lidia Poggio ◽  
Julián Cámara-Hernández ◽  
Graciela Esther González
Keyword(s):  
Genome Size ◽  
Artificial Selection ◽  
Repetitive Sequences ◽  
Flow Cytometry Data ◽  
Similar Variation ◽  
Maize Landraces ◽  
Vegetative Cycle ◽  
Northeastern Argentina ◽  
Heterochromatin Content ◽  
Selection Of

Abstract Variation in genome size and knob heterochromatin content was explored in relationship to altitudinal cline and length of the vegetative cycle in northern Argentina, USA and Mexico landraces. It was considering that the decrease in DNA and heterochromatin content could be an adaptation to a shorter growing season and the result of artificial selection by man. Guaraní landraces from Northeastern Argentina (NEA) show similar variation in genome size (3.81pg to 7.56pg) and knob heterochromatin content than maize growing across an altitudinal cline. The present analysis offers an overview of the genetic variability of NEA maize to explain why Guaraní landraces and those along an altitudinal cline share this similar variation. Karyotype and flow cytometry data were employed. The DNA content of Guaraní landraces which lacking B chromosomes, showed no significant relationship with knob heterochromatin, suggesting differences in the amount of interspersed DNA. A significant positive relationship was found between the length of the vegetative cycle and both number and percentage of knob heterochromatin. No significant correlation was found between genome size and vegetative cycle. All these results allow us to conclude that the variation in heterochromatin content among Guaraní maize is driven by the selection of farmers for flowering time.

scholarly journals Intragenomic Conflict between Knob Heterochromatin and B Chromosomes Is the Key to Understand Genome Size Variation along Altitudinal Clines in Maize

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1859
Author(s):  
Graciela Esther González ◽  
Lidia Poggio
Keyword(s):  
Genome Size ◽  
Size Variation ◽  
B Chromosomes ◽  
Genome Size Variation ◽  
Dapi Staining ◽  
Intragenomic Conflict ◽  
Maize Landraces ◽  
Vegetative Cycle ◽  
Higher Doses

In maize, we studied the causes of genome size variation and their correlates with cultivation altitude that suggests the existence of adaptive clines. To discuss the biological role of the genome size variation, we focused on Bolivian maize landraces growing along a broad altitudinal range. These were analyzed together with previously studied populations from altitudinal clines of Northwestern Argentina (NWA). Bolivian populations exhibited numerical polymorphism for B chromosomes (Bs) (from 1 to 5), with frequencies varying from 16.6 to 81.8 and being positively correlated with cultivation altitude. The 2C values of individuals 0B (A-DNA) ranged between 4.73 and 7.71 pg, with 58.33% of variation. The heterochromatic knobs, detected by DAPI staining, were more numerous and larger in individuals 0B than in those with higher doses of Bs. Bolivian and NWA landraces exhibited the same pattern of A-DNA downsizing and fewer and smaller knobs with increasing cultivation altitude, suggesting a mechanistic link among heterochromatin, genome size and phenology. The negative association between the two types of supernumerary DNA (knob heterochromatin and Bs), mainly responsible for the genome size variation, may be considered as an example of intragenomic conflict. It could be postulated that the optimal nucleotype is the result of such conflict, where genome adjustment may lead to an appropriate length of the vegetative cycle for maize landraces growing across altitudinal clines.

scholarly journals An enormous Paris polyphylla genome sheds light on genome size evolution and polyphyllin biogenesis

2020 ◽  
Author(s):  
Jing Li ◽  
Meiqi Lv ◽  
Lei Du ◽  
A Yunga ◽  
Shijie Hao ◽  
...  
Keyword(s):  
Genome Size ◽  
Single Molecule ◽  
Repetitive Sequences ◽  
Plant Genome ◽  
Growth Stages ◽  
Evolutionary Trend ◽  
Rna Seq ◽  
Genome Size Evolution ◽  
Size Evolution ◽  
Paris Polyphylla

AbstractThe monocot family Melanthiaceae with varying genome sizes in a range of 230-fold is an ideal model to study the genome size fluctuation in plants. Its family member Paris genus demonstrates an evolutionary trend of bearing huge genomes characterized by an average c-value of 49.22 pg. Here, we report a 70.18 Gb genome assembly out of the 82.55 Gb genome of Paris polyphylla var. yunnanensis (PPY), which represents the biggest sequenced genome to date. We annotate 69.53% repetitive sequences in this genome and 62.50% of which are long-terminal repeat (LTR) transposable elements. Further evolution analysis indicates that the giant genome likely results from the joint effect of common and species-specific expansion of different LTR superfamilies, which might contribute to the environment adaptation after speciation. Moreover, we identify the candidate pathway genes for the biogenesis of polyphyllins, the PPY-specific medicinal saponins, by complementary approaches including genome mining, comprehensive analysis of 31 next-generation RNA-seq data and 55.23 Gb single-molecule circular consensus sequencing (CCS) RNA-seq reads, and correlation of the transcriptome and phytochemical data of five different tissues at four growth stages. This study not only provides significant insights into plant genome size evolution, but also paves the way for the following polyphyllin synthetic biology.

scholarly journals Breeding for chemical camouflage the case of salmon kairomones and resistance to salmon lice infectivity

2021 ◽  
Author(s):  
Gareth Difford ◽  
John-Erik Haugen ◽  
Muhammad Luqman Aslam ◽  
Lill-Heidi Johansen ◽  
Mette Breiland ◽  
...  
Keyword(s):  
Artificial Selection ◽  
Farmed Salmon ◽  
Chemical Camouflage ◽  
Salmon Lice ◽  
Selection Of

Abstract Salmon lice are ectoparasites that threaten wild and farmed salmonids. Artificial selection of salmon for resistance to the infectious copepodid lice stage currently relies on in vivo challenge trials on thousands of salmon a year. We found that salmon emit a bouquet of kairomones which the lice use to find and infect the salmon. Some of these compounds vary between families and could be used as a more direct and ethical measurements of lice resistance for breeding farmed salmon.

scholarly journals Artificial selection of reaction norms of wing pattern elements in Bicyclus anynana

Heredity ◽  
1995 ◽  
Vol 74 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Graham J Holloway ◽  
Paul M Brakefield
Keyword(s):  
Artificial Selection ◽  
Reaction Norms ◽  
Wing Pattern ◽  
Bicyclus Anynana ◽  
Selection Of

Reliance Upon a Toxic Staple Crop

2017 ◽  
Author(s):  
Warren Wilson ◽  
Darna L. Dufour
Keyword(s):  
Artificial Selection ◽  
Agricultural Practices ◽  
North West ◽  
The North ◽  
Variety Selection ◽  
Salient Factor ◽  
Staple Crop ◽  
Selection Of

In Amazonia most indigenous horticulturists prefer to cultivate the more toxic forms of manioc as a staple crop, despite the increased processing required to render them safe for consumption. This phenomenon has long intrigued anthropologists. In this chapter we describe the agricultural practices of the Tukanoan Indians in the North-west Amazon and explore their reliance on toxic varieties of manioc from agronomic, ecological, organoleptic, and ethnographic perspectives. Our findings indicate that the puzzling preference for a toxic staple crop may be explained by the higher yields produced by the more toxic forms, and also that the most salient factor in variety selection by Tukanoan women is the food into which the roots will be made. This suggests a multifaceted explanation. Moreover, we propose that present-day lack of concern about yield is a recent luxury due to artificial selection of sufficiently high-yielding manioc varieties during the development of this crop.

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