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2,967 results for “secondary”
Data from: On the origin of sweet potato (Ipomoea batatas (L.) Lam) genetic diversity in New Guinea, a secondary centre of diversity
New Guinea is considered the most important secondary centre of diversity for sweet potato (Ipomoea batatas). We analysed nuclear and chloroplast genetic diversity of 417 New Guinea sweet potato landraces, representing agro-morphological diversity collected throughout the island, and compared this diversity with that in tropical America. The molecular data reveal moderate diversity across all accessions analysed, lower than that found in tropical America. Nuclear data confirm previous results, suggesting that New Guinea landraces are principally derived from the Northern neotropical genepool (Camote and Batata lines, from the Caribbean and Central America). However, chloroplast data suggest that South American clones (early Kumara line clones or, more probably, later reintroductions) were also introduced into New Guinea and then recombined with existing genotypes. The frequency distribution of pairwise distances between New Guinea landraces suggests that sexual reproduction, rather than somaclonal variation, has played a predominant role in the diversification of sweet potato. The frequent incorporation of plants issued from true seed by farmers, and the geographical and cultural barriers constraining crop diffusion in this topographically and linguistically heterogeneous island, has led to the accumulation of an impressive number of variants. As the diversification of sweet potato in New Guinea is primarily the result of farmers' management of the reproductive biology of their crop, we argue that on-farm conservation programmes that implement distribution of core samples (clones representing the useful diversity of the species) and promote on-farm selection of locally adapted variants may allow local communities to fashion relatively autonomous strategies for coping with ongoing global change.
Data from: Diagnosis of crop secondary and micro-nutrient deficiencies in sub-Saharan Africa
Crop production in sub-Saharan Africa has numerous biotic and abiotic constraints, including nutrient deficiencies. Information on crop response to macronutrients is relatively abundant compared with secondary and micronutrients (SMN). Data from 1339 trial replicates of 280 field trials conducted from 2013 to 2016 in 11 countries were analyzed for the diagnosis of SMN deficiencies. The diagnostic data included relative yield response (RYR) and soil and foliar test results. The RYR to application of a combination of Mg, S, Zn, and B (Mg-S-Zn-B) relative to a comparable N-P-K treatment was a >5% increase for 35% of the legume blocks and 60% of the non-legume blocks. The frequencies of soil test Zn, Cu, and B being below their critical level were 28, 2 and 10% for eastern and southern Africa, respectively, and 55, 58 and 89% for western Africa, while low levels for other SMN were less frequent. The frequency of foliar results indicating low availability were 58% for Zn, 16% for S and less for other SMN. The r2 values for relationships between soil test, foliar test and RYR results were <0.035 with little complementarity except for soil test Zn and B with cassava (Manihot esculenta L. Crantz) RYR in Ghana, and foliar Zn with cereal RYR in Uganda. Positive RYR is powerful diagnostic information and indicative of good profit potential for well-targeted and well-specified SMN application. Geo-referenced RYR, soil analysis and foliar analysis results for diagnosis of SMN deficiencies in 11 countries of sub-Saharan Africa were generally not complementary.
Data from: Limits to speciation inferred from times to secondary sympatry and ages of hybridizing species along a latitudinal gradient
Range expansions are critical to renewed bouts of allopatric or parapatric speciation. Limits on range expansions—and, by implication, speciation—include dispersal ability and permeability of geographical barriers. In addition, recently diverged taxa may interfere with each other, preventing mutual expansion of each other's range into sympatry, because reproductive isolation is incomplete and/or ecological competition particularly strong. On the basis of geographical distributions and mitochondrial DNA phylogenetic information for 418 recently diverged species of New World birds, we estimate that secondary sympatry takes on the order of millions of years following population splitting and hence could impose an important limit on the rate of range expansion, thereby limiting further rounds of species formation. Average rates of achievement of sympatry have been faster in the temperate region (we estimate 1.7 million years to sympatry at 60°) than in the tropics (3.2 million years to sympatry at the equator). Evidence from the ages of species with hybrid zones implies that one factor associated with the slowed sympatry in the tropics is the rate of accumulation of reproductive isolation.
Data from: Speciation in sympatry with ongoing secondary gene flow and an olfactory trigger in a radiation of Cameroon cichlids
The process of sympatric speciation in nature remains a fundamental unsolved problem. Cameroon crater lake cichlid radiations were long regarded as one of the most compelling examples; however, recent work showed that their origins were more complex than a single colonization event followed by isolation. Here, we performed a detailed investigation of the speciation history of a radiation of Coptodon cichlids from Lake Ejagham using whole-genome sequencing data. The existence of this radiation is remarkable since this 0.5 km2 lake offers limited scope for divergence across a shallow depth gradient, disruptive selection is weak, and the species are sexually monochromatic. We infer that Lake Ejagham was colonized by riverine cichlids soon after its formation 9,000 years ago, yet speciation occurred only in the last 1,000-2,000 years. We show that secondary gene flow from riverine species has been ongoing, into ancestral and extant Lake Ejagham lineages, and identify and date river-to-lake admixture blocks. One of these contains a cluster of olfactory receptor genes that introgressed close to the time of the first speciation event and coincides with a higher overall rate of admixture into the recipient lineages. Olfactory signaling is a key component of mate choice and species recognition in cichlids. A functional role for this introgression event is consistent with previous findings that assortative mating appears much stronger than ecological divergence in Ejagham Coptodon. We conclude that speciation in this radiation took place in sympatry, yet may have benefited from ongoing riverine gene flow.
FIGURE 5 in A second species of Gegeneophis Peters (Amphibia: Gymnophiona: Caeciliidae) lacking secondary annular grooves
FIGURE 5. Paratypes of Gegeneophis pareshi sp. nov. in life, BNHS 5377 (left, total length = 190 mm) and BNHS 5372 (right, total length 115 mm).
FIGURE 6 in A second species of Gegeneophis Peters (Amphibia: Gymnophiona: Caeciliidae) lacking secondary annular grooves
FIGURE 6. Mixed small plantation in walled garden at Poinguinim, collection locality of eight paratypes of Gegeneophis pareshi sp. nov.
FIGURE 4 in A second species of Gegeneophis Peters (Amphibia: Gymnophiona: Caeciliidae) lacking secondary annular grooves
FIGURE 4. Head end of preserved paratype male and largest specimen (BNHS 5298) of Gegeneophis pareshi sp. nov. Scale bar in mm.
FIGURE 3 in A second species of Gegeneophis Peters (Amphibia: Gymnophiona: Caeciliidae) lacking secondary annular grooves
FIGURE 3. Posterior end of preserved holotype (BNHS 5264) of Gegeneophis pareshi sp. nov. Scale bar in mm.
FIGURE 2 in A second species of Gegeneophis Peters (Amphibia: Gymnophiona: Caeciliidae) lacking secondary annular grooves
FIGURE 2. Anterior end of preserved holotype (BNHS 5264) of Gegeneophis pareshi sp. nov. Scale bar in mm.
FIGURE 1 in A third species of Gegeneophis Peters (Amphibia: Gymnophiona: Indotyphlidae) lacking secondary annular grooves
FIGURE 1. Gegeneophis primus sp. nov. paratopotype ZSI/WGRC/V/A/852 in life, approximately 168 mm total length.
FIGURE 3 in A third species of Gegeneophis Peters (Amphibia: Gymnophiona: Indotyphlidae) lacking secondary annular grooves
FIGURE 3. Map showing the approximate positions of the type localities of the three nominal species of Gegeneophis occurring in Kerala state: 1. G. carnosus (Peria), 2. G. p r i m u s sp. nov. (Sugandhagiri), 3. G. ramaswamii (Thenmalai).
FIGURES 19–24 in Two new tardigrade species from Romania (Eutardigrada: Milnesiidae, Macrobiotidae), with some remarks on secondary sex characters in Milnesium dornensis sp. nov.
FIGURES 19–24. Minibiotus diversus sp. nov.: 19—pores arranged in rows between legs I and II; 20—pores on dorsal side; 21—triangle–like formation of pores on ventral side of head segment; 22—large pores on frontal side of the body (dorsal view); 23–24—large pores on posterior side of the body (dorsal view).
FIGURES 11–14 in Two new tardigrade species from Romania (Eutardigrada: Milnesiidae, Macrobiotidae), with some remarks on secondary sex characters in Milnesium dornensis sp. nov.
FIGURES 11–14. Milnesium dornensis sp. nov. male: 11—modified claws I; 12—claws III; 13—claws IV; 14—accessory point on main branch of claw.
FIGURES 7–10 in Two new tardigrade species from Romania (Eutardigrada: Milnesiidae, Macrobiotidae), with some remarks on secondary sex characters in Milnesium dornensis sp. nov.
FIGURES 7–10. Milnesium dornensis sp. nov. female: 7—claws I; 8—dorsal plates on caudal end; 9—claws IV; 10—accessory point on main branch of claw.
FIGURES 3–6 in Two new tardigrade species from Romania (Eutardigrada: Milnesiidae, Macrobiotidae), with some remarks on secondary sex characters in Milnesium dornensis sp. nov.
FIGURES 3–6. Milnesium dornensis sp. nov. female: 3—buccal apparatus (ventral view); 4—sculpture on dorsal cuticle; male: 5—buccal apparatus; 6—sculpture on dorsal cuticle (ventral view).
FIGURES 25–29 in Two new tardigrade species from Romania (Eutardigrada: Milnesiidae, Macrobiotidae), with some remarks on secondary sex characters in Milnesium dornensis sp. nov.
FIGURES 25–29. Minibiotus diversus sp. nov.: 25–28—granulation on legs I–IV; 29—large pores on external side of the legs II–III (lateral view).
FIGURE 9 in Male secondary sexual characters resolve taxonomic uncertainty: five new species and a review of the formerly monotypic rove beetle genus Mimosticus Sharp (Coleoptera: Staphylinidae: Staphylininae)
FIGURE 9. Abparameral view of median lobe of the aedeagus, showing internal sac in situ: Mimosticus viridipennis, Sharp (A), M. tenuiformis Brunke and Solodovnikov (B), M. aeneipennis Brunke and Solodovnikov (C), M. sharpi Brunke and Solodovnikov (D). Copulatory sclerite of internal sac of M. sharpi (E), M. pseudosharpi Brunke and Solodovnikov (F) and M. latens Brunke and Solodovnikov (G). Scale bars = 0.2 mm. a—ventral apex of paramere showing peg setae-like structures, b—copulatory sclerite, arrow—apical margin of copulatory sclerite.
FIGURE 5 in Male secondary sexual characters resolve taxonomic uncertainty: five new species and a review of the formerly monotypic rove beetle genus Mimosticus Sharp (Coleoptera: Staphylinidae: Staphylininae)
FIGURE 5. Male tergite VIII of M. latens Brunke and Solodovnikov (A). Female tergite X of M. sharpi Brunke and Solodovnikov (B). Scale bars = 1 mm.
FIGURE 6. Male sternite IX in Male secondary sexual characters resolve taxonomic uncertainty: five new species and a review of the formerly monotypic rove beetle genus Mimosticus Sharp (Coleoptera: Staphylinidae: Staphylininae)
FIGURE 6. Male sternite IX of Mimosticus viridipennis, Sharp (A), M. tenuiformis Brunke and Solodovnikov (B), M. aeneipennis Brunke and Solodovnikov (C), M. sharpi Brunke and Solodovnikov (D), M. pseudosharpi Brunke and Solodovnikov (E) and M. latens Brunke and Solodovnikov (F). Scale bars = 0.2 mm.
FIGURE 2. Antennomeres 4–11 in Male secondary sexual characters resolve taxonomic uncertainty: five new species and a review of the formerly monotypic rove beetle genus Mimosticus Sharp (Coleoptera: Staphylinidae: Staphylininae)
FIGURE 2. Antennomeres 4–11: Mimosticus viridipennis, Sharp (A), M. tenuiformis Brunke and Solodovnikov (B), M. aeneipennis Brunke and Solodovnikov (C) and M. sharpi Brunke and Solodovnikov (D). Ventral forebody of M. tenuiformis (E). Mesotrochanter and mesofemur of M. tenuiformis (F). Hindwing of M. aeneipennis, vein MP4 fused to CuA (G). Scale bars = 1 mm.
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Allen Brain Atlas
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Annotated Behaviour and Observability Dataset (ABODe)
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DANDI Archive for NWB datasets
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OpenNeuro
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