Displaying publications 21 - 40 of 53 in total

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  1. ISSR marker-assisted genetic diversity analysis of Dioscorea hispida and selection of the best variety for sustainable production
    Nudin NFH, Ali AM, Ngah N, Mazlan NZ, Mat N, Ghani MNA, et al.
    C. R. Biol., 2017 Aug;340(8):359-366.
    PMID: 28888550 DOI: 10.1016/j.crvi.2017.08.003
    Plant breeding is a way of selection of a particular individual for the production of the progeny by separating or combining desired characteristics. The objective of this study was to justify different characteristics of Dioscorea hispida (Ubi gadong) varieties using molecular techniques to select the best variety for sustainable production at the farmer's level. A total of 160 germplasms of Ubi gadong were collected from different locations at the Terengganu and Kelantan states of Malaysia. Forty eight (48) out of 160 germplasms were selected as "primary" selection based on yield and other qualitative characters. Selected collections were then grown and maintained for ISSR marker-assisted genetic diversity analysis. Overall plant growth and yield of tubers were also determined. A total of 12 ISSR markers were tested to justify the characteristics of Ubi gadong varieties among which three markers showed polymorphic bands and on average 57.3% polymorphism were observed representing the highest variation among germplasms. The ISSR marker based on UPGMA cluster analysis grouped all 48 D. hispida into 10 vital groups that proved a vast genetic variation among germplasm collections. Therefore, hybridization should be made between two distant populations. The D. hispida is already proved as the highest starch content tuber crops and very rich in vitamins with both micro and macro minerals. Considering all these criteria and results from marker-assisted diversity analysis, accessions that are far apart based on their genetic coefficient (like DH27 and DH71; DH30 and DH70; DH43 and DH62; DH45 and DH61; DH77 and DH61; DH78 and DH57) could be selected as parents for further breeding programs. This will bring about greater diversity, which will lead to high productive index in terms of increase in yield and overall quality and for the ultimate target of sustainable Ubi gadong production.
    Matched MeSH terms: Hybridization, Genetic
  2. Interspecific Cross-Mating Between Aedes aegypti and Aedes albopictus Laboratory Strains: Implication of Population Density on Mating Behaviors
    Marcela P, Hassan AA, Hamdan A, Dieng H, Kumara TK
    J Am Mosq Control Assoc, 2015 Dec;31(4):313-20.
    PMID: 26675452 DOI: 10.2987/moco-31-04-313-320.1
    Mating behavior between Aedes aegypti and Ae. albopictus, established colony strains were examined under laboratory conditions (30-cm(3) screened cages) for 5 consecutive days. The effect of selected male densities (30, 20, 10) and female density (20) on the number of swarming, mating pairs, eggs produced, and inseminated females were evaluated. Male densities significantly increased swarming behavior, mating pairs, and egg production of heterospecific females, but female insemination was reduced. Aedes aegypti males mate more readily with heterospecific females than do Ae. albopictus males. The current study suggests that Ae. aegypti males were not species-specific in mating, and if released into the field as practiced in genetically modified mosquito techniques, they may mate with both Ae. aegypti and Ae. albopictus females, hence reducing populations of both species by producing infertile eggs.
    Matched MeSH terms: Hybridization, Genetic*
  3. The inheritance of autogeny in Aedes (Finlaya) togoi (Theobald) from Malaysia and some aspects of its biology
    Thomas V, Leng YP
    Southeast Asian J. Trop. Med. Public Health, 1972 Jun;3(2):163-74.
    PMID: 5082846
    Matched MeSH terms: Hybridization, Genetic
  4. Fulltext Genomic analyses reveal an absence of contemporary introgressive admixture between fin whales and blue whales, despite known hybrids
    Westbury MV, Petersen B, Lorenzen ED
    PLoS One, 2019;14(9):e0222004.
    PMID: 31553763 DOI: 10.1371/journal.pone.0222004
    Fin whales (Balaenoptera physalus) and blue whales (B. musculus) are the two largest species on Earth and are widely distributed across the world's oceans. Hybrids between these species appear to be relatively widespread and have been reported in both the North Atlantic and North Pacific; they are also relatively common, and have been proposed to occur once in every thousand fin whales. However, despite known hybridization, fin and blue whales are not sibling species. Rather, the closest living relative of fin whales are humpback whales (Megaptera novaeangliae). To improve the quality of fin whale data available for analysis, we assembled and annotated a fin whale nuclear genome using in-silico mate pair libraries and previously published short-read data. Using this assembly and genomic data from a humpback, blue, and bowhead whale, we investigated whether signatures of introgression between the fin and blue whale could be found. We find no signatures of contemporary admixture in the fin and blue whale genomes, although our analyses support ancestral gene flow between the species until 2.4-1.3 Ma. We propose the following explanations for our findings; i) fin/blue whale hybridization does not occur in the populations our samples originate from, ii) contemporary hybrids are a recent phenomenon and the genetic consequences have yet to become widespread across populations, or iii) fin/blue whale hybrids are under large negative selection, preventing them from backcrossing and contributing to the parental gene pools.
    Matched MeSH terms: Hybridization, Genetic
  5. Genetic analysis of samples from wild populations opens new perspectives on hybridization between long-tailed (Macaca fascicularis) and rhesus macaques (Macaca mulatta)
    Bunlungsup S, Kanthaswamy S, Oldt RF, Smith DG, Houghton P, Hamada Y, et al.
    Am J Primatol, 2017 12;79(12).
    PMID: 29095514 DOI: 10.1002/ajp.22726
    In the past decade, many researchers have published papers about hybridization between long-tailed and rhesus macaques. These previous works have proposed unidirectional gene flow with the Isthmus of Kra as the zoogeographical barrier of hybridization. However, these reports analyzed specimens of unknown origin and/or did not include specimens from Thailand, the center of the proposed area of hybridization. Collected specimens of long-tailed and rhesus macaques representing all suspected hybridization areas were examined. Blood samples from four populations each of long-tailed and rhesus macaques inhabiting Thailand, Myanmar, and Laos were collected and analyzed with conspecific references from China (for rhesus macaques) and multiple countries from Sundaic regions (for long-tailed macaques). Ninety-six single nucleotide polymorphism (SNP) markers specifically designed to interrogate admixture and ancestry were used in genotyping. We found genetic admixture maximized at the hybrid zone (15-20°N), as well as admixture signals of varying strength in both directions outside of the hybrid zone. These findings show that the Isthmus of Kra is not a barrier to gene flow from rhesus to long-tailed populations. However, to precisely identify a southernmost barrier, if in fact a boundary rather than simple isolation by distance exists, the samples from peninsular Malaysia must be included in the analysis. Additionally, a long-tailed to rhesus gene flow boundary was found between northern Thailand and Myanmar. Our results suggest that selection of long-tailed and rhesus macaques, the two most commonly used non-human primates for biomedical research, should take into account not only the species identification but also the origin of and genetic admixture within and between the species.
    Matched MeSH terms: Hybridization, Genetic*
  6. A Natural Population Derived from Species Hybridizationin the Drosophila ananassae Species Complexon Penang Island, Malaysia
    Sawamura K, Sato H, Lee CY, Kamimura Y, Matsuda M
    Zoolog Sci, 2016 Oct;33(5):467-475.
    PMID: 27715417
    We surveyed natural population of the Drosophila ananassae species complex on Penang Island, Malaysia. Analyses of phenotypic traits, chromosome arrangements, molecular markers, and reproductive isolation suggest the existence of two species: D. ananassae and D. cf. parapallidosa. Molecular marker analysis indicates that D. cf. parapallidosa carries chromosome Y and 4 introgressions from D. ananassae. Thus, D. cf. parapallidosa seems to be a hybrid descendant that recently originated from a natural D. parapallidosa♀× D. ananassae♂ cross. Furthermore, D. cf. parapallidosa behaves differently from authentic D. parapallidosa with respect to its reproductive isolation from D. ananassae. Premating isolation is usually seen in only the D. ananassae♀× D. parapallidosa♂ cross, but we observed it in crosses of both directions between D. ananassae and D. cf. parapallidosa. In addition, hybrid males from the D. ananassae♀× D. parapallidosa♂ cross are usually sterile, but they were fertile when D. ananassae♀ were mated with D. cf. parapallidosa ♂. We attempted an artificial reconstruction of the hybrid species to simulate the evolutionary process(es) that produced D. cf. parapallidosa. This is a rare case of natural hybrid population in Drosophila and may be a useful system for elucidating speciation with gene flow.
    Matched MeSH terms: Hybridization, Genetic
  7. Fulltext A Cross-Species Gene Expression Marker-Based Genetic Map and QTL Analysis in Bambara Groundnut
    Chai HH, Ho WK, Graham N, May S, Massawe F, Mayes S
    Genes (Basel), 2017 Feb 22;8(2).
    PMID: 28241413 DOI: 10.3390/genes8020084
    Bambara groundnut (Vigna subterranea (L.) Verdc.) is an underutilised legume crop, which has long been recognised as a protein-rich and drought-tolerant crop, used extensively in Sub-Saharan Africa. The aim of the study was to identify quantitative trait loci (QTL) involved in agronomic and drought-related traits using an expression marker-based genetic map based on major crop resources developed in soybean. The gene expression markers (GEMs) were generated at the (unmasked) probe-pair level after cross-hybridisation of bambara groundnut leaf RNA to the Affymetrix Soybean Genome GeneChip. A total of 753 markers grouped at an LOD (Logarithm of odds) of three, with 527 markers mapped into linkage groups. From this initial map, a spaced expression marker-based genetic map consisting of 13 linkage groups containing 218 GEMs, spanning 982.7 cM (centimorgan) of the bambara groundnut genome, was developed. Of the QTL detected, 46% were detected in both control and drought treatment populations, suggesting that they are the result of intrinsic trait differences between the parental lines used to construct the cross, with 31% detected in only one of the conditions. The present GEM map in bambara groundnut provides one technically feasible route for the translation of information and resources from major and model plant species to underutilised and resource-poor crops.
    Matched MeSH terms: Hybridization, Genetic
  8. Fulltext Void Content, Tensile, Vibration and Acoustic Properties of Kenaf/Bamboo Fiber Reinforced Epoxy Hybrid Composites
    Ismail AS, Jawaid M, Naveen J
    Materials (Basel), 2019 Jun 28;12(13).
    PMID: 31261821 DOI: 10.3390/ma12132094
    This study aims to investigate the void content, tensile, vibration and acoustic properties of kenaf/bamboo fiber reinforced epoxy hybrid composites. The composites were made using the hand lay-up method. The weight ratios of kenaf/bamboo were 30:70, 50:50 and 70:30. Further, kenaf and bamboo composites were fabricated for the purpose of comparison. The hybridization of woven kenaf/bamboo reduced the void content. The void contents of hybrid composites were almost similar. An enhancement in elongation at break, tensile strength and modulus of hybrid composites was observed until a kenaf/bamboo ratio of 50:50. Kenaf/bamboo (50:50) hybrid composite displays the highest elongation at break, tensile strength and modulus compared to the other hybrid composites which are 2.42 mm, 55.18 MPa and 5.15 GPa, respectively. On the other hand, the highest natural frequency and damping factors were observed for Bamboo/Kenaf (30:70) hybrid composites. The sound absorption coefficient of composites were measured in two conditions: without air gap and with air gap (10, 20, 30 mm). The sound absorption coefficient for testing without air gap was less than 0.5. Introducing an air gap improved the sound absorption coefficient of all composites. Hence, hybrid kenaf/bamboo composites exhibited less void content, as well as improved tensile, vibration and acoustic properties.
    Matched MeSH terms: Hybridization, Genetic
  9. Fulltext Molecular evidence of the hybrid origin of Cryptocoryne ×purpurea Ridl. nothovar. purpurea (Araceae)
    Rosazlina R, Jacobsen N, Ørgaard M, Othman AS
    PLoS One, 2021;16(1):e0239499.
    PMID: 33476321 DOI: 10.1371/journal.pone.0239499
    Natural hybridization has been considered a source of taxonomic complexity in Cryptocoryne. A combined study of DNA sequencing data from the internal transcribed spacer (ITS) of nuclear ribosomal DNA and the trnK-matK region of chloroplast DNA was used to identify the parents of Cryptocoryne putative hybrids from Peninsular Malaysia. Based on the intermediate morphology and sympatric distribution area, the plants were tentatively identified as the hybrid Cryptocoryne ×purpurea nothovar. purpurea. The plants were pollen sterile and had long been considered as hybrids, supposedly between two related and co-existing species, C. cordata var. cordata and C. griffithii. The status of C. ×purpurea nothovar. purpurea was independently confirmed by the presence of an additive ITS sequence pattern from these two parental species in hybrid individuals. An analysis of the chloroplast trnK-matK sequences showed that the hybridization is bidirectional with the putative hybrids sharing identical sequences from C. cordata var. cordata and C. griffithii, indicating that both putative parental species had been the maternal parent in different accessions.
    Matched MeSH terms: Hybridization, Genetic/genetics
  10. Hybridomas--medical diagnosis of the future
    Pang T
    Med J Malaysia, 1979 Dec;34(2):91-4.
    PMID: 398437
    Matched MeSH terms: Hybridization, Genetic*
  11. Cloning and expression of Vibrio cholerae virulence gene, accessory cholera enterotoxin (ace)
    Somarny WM, Mariana NS, Rozita R, Raha AR
    Southeast Asian J. Trop. Med. Public Health, 2004 Dec;35(4):856-62.
    PMID: 15916081
    The cholera enterotoxin (CT) has been considered a major virulence factor of Vibrio cholerae. The accessory cholera enterotoxin (ace) gene is the third gene of V. cholerae virulence cassette. The gene coding for the Ace toxin was amplified from V. cholerae isolates producing a single band of 314 bp. The presence of ace gene was confirmed by hybridization as well as by sequencing. The gene was successfully expressed in Escherichia coli (LMG194) using expression, pBAD/Thio-TOPO vector. Optimal conditions for expression included choice of host strain, temperature used for culturing, and concentration of antibiotic and arabinose inducer. The Ace protein was obtained from the cell supernatant as a fusion protein with a molecular mass 34 kDa which was detected using an anti V5-HRP epitope tagged antibody.
    Matched MeSH terms: Hybridization, Genetic
  12. Fulltext Empirical investigation of feature sets effectiveness in product review sentiment classification
    Nurfadhlina Mohd Sharef, Rozilah Rosli
    Pertanika Journal of Science & Technology, 2017;25(106):125-132.
    MyJurnal
    Sentiment analysis classification has been typically performed by combining features that represent the dataset at hand. Existing works have employed various features individually such as the syntactical, lexical and machine learning, and some have hybridized to reach optimistic results. Since the debate on the best combination is still unresolved this paper addresses the empirical investigation of the combination of features for product review classification. Results indicate the Support Vector Machine classification model combined with any of the observed lexicon namely MPQA, BingLiu and General Inquirer and either the unigram or inte-gration of unigram and bigram features is the top performer.
    Matched MeSH terms: Hybridization, Genetic
  13. Fulltext Induced tensile properties with EB- cross linking of hybridized kenaf/palf reinforced HDPE composite
    Aji, I.S., Zinudin, E.S., Khairul, M.Z., Abdan, K., S. M. Sapuan
    Pertanika Journal of Science & Technology, 2013;21(1):135-140.
    MyJurnal
    Electron beam irradiation, without any addition of cross-linking agents, was investigated at varying
    doses of EB-Irradiation to develop an environmentally friendly hybridized kenaf (bast)/ pineapple leaf
    fibre (PALF) bio-composites. Improvement in tensile property of the hybrid was achieved with the result
    showing a direct proportionality relationship between tensile properties and increasing radiation dose.
    Statistical analysis software (SAS) was employed to validate the result. HDPE has been shown to have
    self-cross-linked, enabling interesting tensile properties with irradiation. Statistical analysis validated
    the results obtained and also showed that adequate mixing of fibres and matrix had taken place at 95%
    confidence level. Hybridization and subsequent irradiation increased the tensile strength and modulus
    of HDPE up to 31 and 185%, respectively, at about 100kGy. Meanwhile, SEM was used to view the
    interaction between the fibres and matrix.
    Matched MeSH terms: Hybridization, Genetic
  14. Variation of C-bands in the chromosomes of several subspecies of Rattus rattus
    Yosida TH, Sagai T
    Chromosoma, 1975;50(3):283-300.
    PMID: 1149576
    All subspecies of black rats (Rattus rattus) used in the present study are characterized by having large and clear C-bands at the centromeric region. The appearance of the bands, however, is different in the subspecies. Chromosome pair No. 1 in Asian type black rats (2n=42), which are characterized by an acrocentric and subtelocentric polymorphism, showed C-band polymorphism. In Phillipine rats (R. rattus mindanensis) the pair was subtelocentric with C-bands, but in Malayan black rats (R. rattus diardii) it was usually acrocentric with C-bands. In Hong-Kong (R. rattus flavipectus) and Japanese black rats (R. rattus tanezumi) it was polymorphic with respect to the presence of acrocentrics with C-bands or subtelocentrics without C-bands. The other chromosomes pairs showed clear C-bands, but in Hong-Kong black rats the pairs No. 2 and 5 were polymorphic with and without C-bands. In Japanese black rats, 6 chromosome pairs (No. 3, 4, 7, 9, 11 and 13) were polymorphic in regard to presence and absence of C-bands, but the other 5 chromosome pairs (No. 2, 5, 6, 8 and 10) showed always absence of C-bands. Only pair No. 12 usually showed C-bands. C-bands in small metacentric pairs (No. 14 to 20) in Asian type black rats generally large in size, but those in the Oceanian (2n=38) and Ceylon type black rats (2n=40) were small. In the hybrids between Asian and Oceanian type rats, heteromorphic C-bands, one large and the other small, were observed. Based on the consideration of karyotype evolution in the black rats, the C-band is suggested to have a tendency toward the diminution as far as the related species are concerned.
    Matched MeSH terms: Hybridization, Genetic
  15. Fulltext A classical genetic solution to enhance the biosynthesis of anticancer phytochemicals in Andrographis paniculata Nees
    Valdiani A, Talei D, Tan SG, Abdul Kadir M, Maziah M, Rafii MY, et al.
    PLoS One, 2014;9(2):e87034.
    PMID: 24586262 DOI: 10.1371/journal.pone.0087034
    Andrographolides, the diterpene lactones, are major bioactive phytochemicals which could be found in different parts of the medicinal herb Andrographis paniculata. A number of such compounds namely andrographolide (AG), neoandrographolide (NAG), and 14-deoxy-11,12-didehydroandrographolide (DDAG) have already attracted a great deal of attention due to their potential therapeutic effects in hard-to-treat diseases such as cancers and HIV. Recently, they have also been considered as substrates for the discovery of novel pharmaceutical compounds. Nevertheless, there is still a huge gap in knowledge on the genetic pattern of the biosynthesis of these bioactive compounds. Hence, the present study aimed to investigate the genetic mechanisms controlling the biosynthesis of these phytochemicals using a diallel analysis. The high performance liquid chromatography analysis of the three andrographolides in 210 F1 progenies confirmed that the biosynthesis of these andrographolides was considerably increased via intraspecific hybridization. The results revealed high, moderate and low heterosis for DDAG, AG and NAG, respectively. Furthermore, the preponderance of non-additive gene actions was affirmed in the enhancement of the three andrographolides contents. The consequence of this type of gene action was the occurrence of high broad-sense and low narrow-sense heritabilities for the above mentioned andrographolides. The prevalence of non-additive gene action suggests the suitability of heterosis breeding and hybrid seed production as a preferred option to produce new plant varieties with higher andrographolide contents using the wild accessions of A. paniculata. Moreover, from an evolutionary point of view, the occurrence of population bottlenecks in the Malaysian accessions of A. paniculata was unveiled by observing a low level of additive genetic variance (VA ) for all the andrographolides.
    Matched MeSH terms: Hybridization, Genetic/genetics
  16. First report on the successful hybridization of Pangasianodon hypophthalmus (Sauvage, 1878) and Clarias gariepinus (Burchell, 1822)
    Okomoda VT, Koh ICC, Shahreza MS
    Zygote, 2017 Aug;25(4):443-452.
    PMID: 28635581 DOI: 10.1017/S0967199417000259
    Breeding and larval performance of novel hybrids from reciprocal crosses of Asian catfish Pangasianodon hypophthalmus (Sauvage, 1878) and African catfish Clarias gariepinus (Burchell, 1822) were investigated in this study. Spawning was by hormonal injection of brood fish, artificial fertilization, and incubation in triplicate aquarium tanks (0.5 × 0.5 × 0.5 m3) with continuous aeration. Reciprocal crosses (♀C. gariepinus × ♂P. hypophthalmus and ♀P. hypophthalmus × ♂C. gariepinus) had lower hatchability (≤50%) than their pure siblings (≥75%). Fish from all crosses survived until the juvenile stage but survival at 35 days post hatching (dph) was higher for pure C. gariepinus sib. ♀C. gariepinus × ♂P. hypophthalmus was observed to be less resistant to degradation of water quality than the other crosses, however it had higher body weight compared with the other crosses that showed similar performance. Morphological comparison of surviving juvenile at 35 dph, showed that all ♀P. hypophthalmus × ♂C. gariepinus and 13% of the ♀C. gariepinus × ♂P. hypophthalmus exhibited the very same morphology as that of their maternal parent species, while the other portion of the ♀C. gariepinus × ♂P. hypophthalmus cross exhibited morphological traits that were intermediate between those of both parent species. This study been the first successful attempt to hybridize both species and therefore, laid the groundwork for further studies on the aquaculture potentials of the novel hybrids.
    Matched MeSH terms: Hybridization, Genetic
  17. Fulltext Dataset for the morphological and erythrocytes parameters of Clarias gariepinus, Pangasianodon hypophthalmus, and their reciprocal hybrids
    Okomoda VT, Koh ICC, Hassan A, Oladimeji AS, Ikhwanuddin M, Abol-Munafi AB, et al.
    Data Brief, 2020 Oct;32:106151.
    PMID: 32904264 DOI: 10.1016/j.dib.2020.106151
    Discrimination of different fishes can be done through different means which includes morphological appearance. When two fishes are successfully hybridized, they produce progenies that have shared morphology between their pure parent, hence, making morphometric characterization an important aspect of hybrid discrimination. However, erythrocyte characterization is also a simpler method for characterization. The dataset presented in this article represents the traditional morphological data, truss network data and erythrocyte data of pure and novel hybrids from reciprocal crosses of African catfish Clarias gariepinus and Asian catfish Pangasianodon hypophthalmus. Breeding of the broodstocks was done to produce pure and hybrid progenies which were maintained for a period of four to six months. Based on the cross combinations and morphotypes, traditional measurement of twenty-five morphological characters and five meristic counts were recorded. Thereafter pictures of the different fish groups were used to determine values of thirty-six distances between ten landmark points. The morphological abnormality of the hybrids at market size is also presented in this data article for the very first time. Blood was then collected from the caudal peduncle of ten fish per group and smeared on a slide for observation under a compound microscope (at 100 × magnification). Data gotten included erythrocytes parameters such as cell major axis, cell minor axis, nucleus major axis, nucleus minor axis cell area, nucleus area, cell volume, and nucleus volume. Data recording was through the Microsoft excel spreadsheet; which was also used to process the data to get the exclusive ranges of values for paired progenies. The data as presented is associated with the research article "Morphological characterization of the progenies of pure and reciprocal crosses of Pangasianodon hypophthalmus (Sauvage, 1878) and Clarias gariepinus (Burchell, 1822)" [1]. The dataset presented in this article can be used for easy identification of the novel hybrid progenies of the African Catfish and Asian Catfish.
    Matched MeSH terms: Hybridization, Genetic
  18. Absence of postzygotic isolating mechanisms: evidence from experimental hybridization between two species of tropical sea urchins
    Rahman MA, Uehara T, Arshad A, Yusoff FM, Shamsudin MN
    J Zhejiang Univ Sci B, 2012 Oct;13(10):797-810.
    PMID: 23024047
    Two reef margin species of tropical sea urchins, Echinometra sp. C (Ec) and Echinometra oblonga (Eo), occur sympatrically on Okinawa intertidal reefs in southern Japan. Hybridization between these species was examined through a series of cross-fertilization experiments. At limited sperm concentrations, where conspecific crosses reached near 100% fertilization, both heterospecific crosses showed high fertilization rates (81%-85%). The compatibility of the gametes demonstrated that if gamete recognition molecules are involved in fertilization of these species, they are not strongly species-specific. We found that conspecific crosses reached peak fertilization levels much faster than did heterospecific crosses, indicating the presence of a prezygotic barrier to hybridization in the gametes. Larval survival, metamorphosis, and juvenile and adult survival of hybrid groups were nearly identical to those of their parent species. Hybrids from crosses in both directions developed normally through larval stages to sexually mature adults, indicating that neither gametic incompatibility nor hybrid inviability appeared to maintain reproductive isolation between these species. In adults, Ec×Ec crosses gave the highest live weight, followed by Eo (ova)×Ec (sperm), Ec (ova)×Eo (sperm), and Eo×Eo. Other growth performance measures (viz., test size, Aristotle's lantern length, and gonad index) of hybrid groups and their parental siblings showed the same trends. The phenotypic color patterns of the hybrids were closer to the maternal coloration, whereas spine length, tube-foot and gonad spicule characteristics, pedicellaria valve length, and gamete sizes showed intermediate features. Adult F(1) hybrids were completely fertile and displayed high fertilization success in F(1) backcrosses, eliminating the likelihood that hybrid sterility is a postzygotic mechanism of reproductive isolation. Conversely, intensive surveys failed to find hybrid individuals in the field, suggesting the lack or rarity of natural hybridization. This strongly suggests that reproductive isolation is achieved by prezygotic isolating mechanism(s). Of these mechanisms, habitat segregation, gamete competition, differences in spawning times, gametic incompatibility or other genetic and non-genetic factors appear to be important in maintaining the integrity of these species.
    Matched MeSH terms: Hybridization, Genetic
  19. Fulltext Expression of fatty acid and triacylglycerol synthesis genes in interspecific hybrids of oil palm
    Ting NC, Sherbina K, Khoo JS, Kamaruddin K, Chan PL, Chan KL, et al.
    Sci Rep, 2020 10 01;10(1):16296.
    PMID: 33004875 DOI: 10.1038/s41598-020-73170-5
    Evaluation of transcriptome data in combination with QTL information has been applied in many crops to study the expression of genes responsible for specific phenotypes. In oil palm, the mesocarp oil extracted from E. oleifera × E. guineensis interspecific hybrids is known to have lower palmitic acid (C16:0) content compared to pure African palms. The present study demonstrates the effectiveness of transcriptome data in revealing the expression profiles of genes in the fatty acid (FA) and triacylglycerol (TAG) biosynthesis processes in interspecific hybrids. The transcriptome assembly yielded 43,920 putative genes of which a large proportion were homologous to known genes in the public databases. Most of the genes encoding key enzymes involved in the FA and TAG synthesis pathways were identified. Of these, 27, including two candidate genes located within the QTL associated with C16:0 content, showed differential expression between developmental stages, populations and/or palms with contrasting C16:0 content. Further evaluation using quantitative real-time PCR revealed that differentially expressed patterns are generally consistent with those observed in the transcriptome data. Our results also suggest that different isoforms are likely to be responsible for some of the variation observed in FA composition of interspecific hybrids.
    Matched MeSH terms: Hybridization, Genetic/genetics
  20. Fulltext Ancestry, Plasmodium cynomolgi prevalence and rhesus macaque admixture in cynomolgus macaques (Macaca fascicularis) bred for export in Chinese breeding farms
    Zhang X, Meng Y, Houghton P, Liu M, Kanthaswamy S, Oldt R, et al.
    J Med Primatol, 2017 04;46(2):31-41.
    PMID: 28266719 DOI: 10.1111/jmp.12256
    BACKGROUND: Most cynomolgus macaques (Macaca fascicularis) used in the United States as animal models are imported from Chinese breeding farms without documented ancestry. Cynomolgus macaques with varying rhesus macaque ancestry proportions may exhibit differences, such as susceptibility to malaria, that affect their suitability as a research model.

    METHODS: DNA of 400 cynomolgus macaques from 10 Chinese breeding farms was genotyped to characterize their regional origin and rhesus ancestry proportion. A nested PCR assay was used to detect Plasmodium cynomolgi infection in sampled individuals.

    RESULTS: All populations exhibited high levels of genetic heterogeneity and low levels of inbreeding and genetic subdivision. Almost all individuals exhibited an Indochinese origin and a rhesus ancestry proportion of 5%-48%. The incidence of P. cynomolgi infection in cynomolgus macaques is strongly associated with proportion of rhesus ancestry.

    CONCLUSIONS: The varying amount of rhesus ancestry in cynomolgus macaques underscores the importance of monitoring their genetic similarity in malaria research.

    Matched MeSH terms: Hybridization, Genetic
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