Genetic diversity and population structure of cotton (<i>Gossypium</i>spp.) of the New World assessed by SSR markers
Bibliographic record
Abstract
A global analysis of cotton (Gossypium spp.) genetic diversity is the first step to understanding its geographical distribution, dissemination, genetic relatedness, and population structure. To assess the genetic diversity and population structure in Gossypium species, 111 cotton accessions representing five allotetraploids (AD1–AD5genomes), 23 Asiatic diploids of the Old World (A1and A2genomes), and 82 diploids of the New World subgenus Houzingenia (D1–D11genomes) species were assessed using simple sequence repeats (SSR) markers with wide genome coverage. The mean genetic distance (GD) between the two most important New World tetraploid cottons (Upland (Gossypium hirsutum L.) and Pima (Gossypium barbadense L.)) was 0.39. Among the three shrub type sections (Houzingenia, Integrifolia, and Caducibracteolata) and three arborescent sections (Erioxylum, Selera, and Austroamericana), the GD ranged between 0.19 and 0.41. Phylogenetic analyses clustered all species into distinct phylogenetic groups, which were consistent with genomic origin, evolutionary history, and geographic distribution or ecotypes of these accessions, suggesting the existence of clear structured strata. With all of the genomes, the highest statistical analysis of Structure test through measurements of ad hoc (ΔK) occurred at K = 2, with group Q1 with the Old World diploid A genomes and with group Q2 with all the New World diploids of the D genome. AD genome accessions shared nearly equal alleles from both Q1 and Q2 groups. With all of the diploids of the New World D genomes, the highest value of ΔK occurred at K = 5. These results are consistent with the fundamental knowledge of tetraploid AD-genome formation and the rapid radiation of the American diploid cotton linage that took place somewhere in southwestern Mexico, followed by a differentiation–speciation during angiosperm evolution. In addition, SSR markers provide an alternative solution for distinguishing phylogenetic relationships between accessions of different ecotypes and for elucidating population structure of cottons of the New World.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".