Horizontal gene transfer (HGT) between different organisms is one of the primary forces driving evolution. Recent advances in sequencing and genome analysis technologies have enabled the discovery of evidence for HGT from a wide range of eukaryotic genomes. It is well established that parasitic or symbiotic organisms can transfer genes to their hosts via viruses or transposons. Furthermore, there have been reports of horizontal transfer from one cell to another by apoptotic vesicles or exosomes. This suggests that they may play a role in the onset and recurrence of human diseases, including cancer and metabolic diseases. In this review, we present newly reported cases of HGT in eukaryotic organisms and discuss future research trends.

The life cycle of edible brown alga Cladosiphon okamuranus is composed of two generations, sporophyte and gametophyte, with parthenogenesis of asexual zoids and gametes. Regardless of the origin of a motile cell, almost all microthalli, except for a prostrate filament, experience prostrate disks with assimilatory filaments as their developmental steps. The disks from different origins are morphologically undistinguishable resulting in confusion of ‘seed’ cultures in factual cultivation scenes. In this study, we therefore attempted to characterize the prostrate disks morphologically by using haploid and diploid strains of C. okamuranus, which were maintained by parthenogenesis. Two types of prostrate disks, a disk with long assimilatory filament (long type) and a disk with short assimilatory filament (short type), were identified in the diploid culture and their appearance ratios were influenced by temperature, although the haploid strain possessed only short type. The long type showed a similar morphology to the disks on culture nets harvested from an actual cultivation site. Our results imply that this morphological differentiation (dimorphism) in the diploid strain may be a divergent step between macrothallus bearing unilocular sporangia or microthallus bearing only plurilocular sporangia, and water temperature may be one of the key regulatory factors for the morphogenesis in dimorphism.

In the present study 18 populations of Ledebouria revoluta were investigated for their male meiosis and pollen morphology to understand the diversity in the meiotic course and to know whether the pollen size and viability correlate to its chromosome numbers. Three gametic chromosome counts were observed, i.e., n=15, 30, and 45 indicating the presence of three cytotypes. Various stages, including diakinesis, metaphase I, anaphase I, telophase I, metaphase II, anaphase II, and tetrads were observed. Meiotic anomalies such as laggards and bridge formation were observed. Laggards were observed in BU and AS populations, while bridge formation was observed in PH, RA, and BUT populations. Both laggards and bridge formation were observed in BA and JU populations. Pollen viability was assessed for all the populations and the values ranged from 99.12% (NE population) to 65.48 (AS population). In general, the viability percentage was more than 80%. Pollen features of the L. revoluta populations were examined for the first time. Pollen grains were monosulcate, heteropolar, elliptical, and oblate. The highest (23.57±0.52 µm) polar length (P) was observed in JU population and the lowest (17.34±0.59 µm) in AR population. The increase in chromosome number did not affect the size or morphology of the pollen grains.

In this study, 26 wild strains of Haematococcus spp. collected from different locations around the world were cultured in autotrophic medium (MES-volvox) or mixotrophic medium (MM2). The cell proliferation ability, biomass production (dry weight), and dead cell rate of each culture were measured to compare the astaxanthin synthesis ability. These strains could be grouped into a monophyletic group consisting of five clades by molecular phylogenetic analysis. They were found to consist of 20 strains of Haematococcus pluvialis, 4 strains of Haematococcus rubicundus, and 2 strains of Haematococcus rubens. Although there were clear differences in cell proliferation and astaxanthin synthesis ability among the strains, no specific characteristics were found for each clade as revealed by molecular phylogenetic analysis. Particularly, in MM2 medium, there were large differences among strains in the efficiencies of using acetic acid as a carbon source and amino acids as a nitrogen source. Carotenoid analysis by high-performance liquid chromatography (HPLC) revealed that the SCCAP K-0084 strain accumulated the most astaxanthin per dry weight under both autotrophic (MES-volvox) and mixotrophic (MM2) conditions.

Detailed karyological analyses of the Nigelleae tribe which includes taxa belonging to both genera Garidella and Nigella were performed. All studied taxa are diploid with 2n=12 and all the chromosomes are Ranunculus-type, chromosome size is large, and all taxa exhibit metacentric chromosomes. The karyotype formulas for Nigella and Garidella are 10m+2st and 12m, respectively, and only Nigella orientalis has satellite (SAT) chromosomes among the studied taxa. Secondary constrictions were documented in N. elata and N. orientalis. Genome size was determined using flow cytometry (FCM) and 2C genome sizes of some diploid Nigella species ranged from 21.25 to 23.48 pg. In contrast, a much smaller genome size, 17.68 pg, was determined in Garidella nigellastrum. UPGM cluster analyses were carried out to evaluate the correspondence between chromosomal features and the taxonomy of the tribe. The results showed that karyological parameters are highly useful in taxonomic delimitation at the generic level.

Cymbopogon olivieri is one of the important species belonging to the family Poaceae. The natural habitat of this plant is tropical regions. In particular, it is distributed in tropical and subtropical regions of Africa, Asia, and America. Two species, C. olivieri and C. parkeri have been reported in Iran. The genus has been proven to possess antioxidant, antimicrobial, and antibacterial properties. Taxonomic identification and species classifying of Lemongrass is very difficult due to the ease of cross-breeding and the existence of a large number of species and races. This study aimed to study variations and clustering of 10 Iranian endemic populations of C. olivieri (Boiss.) Bor based on chromosomal and holoploid genome size features. The results of karyotype analysis clearly showed the mixed-ploidy. Among which, six populations were diploids (2n=2x=20), three tetraploids (2n=4x=40), and a hexaploid (2n=6x=60). The mean chromosome length (CL) was determined as 1.87 µm for diploids, 1.73 µm for tetraploids, and 1.25 µm for a hexaploid. The average holoploid genome sizes of the diploids, tetraploids, and a hexaploid were 4.42, 4.64, and 4.91 pg, respectively. These results may provide relevant information for Cymbopogon breeding studies.

Heavy-ion beams are widely used for mutagenesis. The type and size of the induced mutations vary depending on the ion species and velocity. DNA damage response of male gametes during pollen tube growth has been investigated using heavy-ion beam irradiation to the pollen of Cyrtanths mackerii (Amaryllidaceae), indicating that DNA damage induced by argon-ion beam is more difficult to repair than that by carbon-ion beam. In this study, we investigated the effects of DNA damage or mutations in the male gametes with argon-ion irradiation on double fertilization and subsequent embryo and endosperm development and compared the results with carbon-ion irradiation. In immature seeds after pollination with argon-ion-irradiated pollen grains at 10 Gy, there were two types of embryo sacs with embryo and endosperm and with egg cell/zygote and endosperm. The proportion of embryo sacs in the latter type was higher when using argon-ion-irradiated pollen than carbon-ion-irradiated pollen at 40 Gy, suggesting that qualitative differences between the two kinds of irradiation influenced embryo development. In many endosperms after pollination with the irradiated pollen, abnormal chromosome separation and enlarged endosperm nuclei were observed. This indicated that the chromosomal abnormalities in the irradiated male gametes were transmitted to the endosperm nuclei. The enlarged nucleus formation was higher in pollen irradiated with an argon-ion beam than in that with a carbon-ion beam. In conclusion, argon-ion beams, even at low doses, induce distinctive development of embryo and endosperm, making them valuable for investigating double fertilization.

The chromosomal characteristics of three Bauhinia species, namely, B. acuminata, B. purpurea, and B. variegata, were analyzed using orcein, chromomycin A₃ (CMA), and 4′,6-diamidino-2-phenylindole (DAPI) staining. The studied three Bauhinia species had similar diploid chromosome numbers i.e., 2n=28, with all the chromosomes being metacentric. The combined length of the diploid chromosome sets for B. acuminata, B. purpurea, and B. variegata was 35.60 µm, 51.48 µm, and 37.91 µm, respectively. With CMA-staining, two entirely fluoresced chromosomes were present in B. purpurea, while B. acuminata and B. variegata did not show any visible CMA-banded chromosomes. The number of DAPI-bands exhibited variation in these species, such as 12 in B. acuminata and B. purpurea and four in B. variegata. The percentage of AT-rich chromatin was the highest in B. acuminata (67.50%) and the lowest in B. variegata (22.95%). Therefore, each species could be identified using the cytogenetic data obtained from this study.

Plestiodon capito is a reptile endemic to China, but its karyotype has not been reported. Here, we performed chromosome analyses of mitosis and meiosis in P. capito. Chromosomes were prepared directly using bone marrow and testes. Chromosome characteristics were analyzed by Giemsa staining and Ag-NOR banding. The results showed that the diploid chromosome number of P. capito was 2n=26, and the fundamental number (NF) was 46 in both males and females. The types of chromosomes were present as 10 large metacentric, 2 medium metacentric, 8 small metacentric, and 6 small telocentric chromosomes. Nucleolar organizer regions (NORs) were located in the telomere region on the long arm of chromosome pair 7. There was no observation of strange size chromosomes related to sex. We found that during metaphase I, the homologous chromosomes showed synapsis, which can be defined as 13 bivalents and 13 haploid chromosomes at metaphase II as a diploid species. The karyotype formula is as follows: 2n=26=L^m₁₀+M^m₂+S^m₈+S^t₆.

The detailed karyomorphological studies were undertaken for two varieties of Coix lacryma-jobi L., namely C. lacryma-jobi var. puellarum (Balansa) E.G. Camus & A. Camus and C. lacryma-jobi var. ma-yuen (Rom.Caill.) Stapf. The present communication deals with meiotic and somatic chromosome numbers, total chromosome length, arm ratio, centromeric position, and Stebbins classification. Somatic chromosome number 2n=20 and meiotic number n=10 were observed in both varieties. Karyotypes of both varieties of C. lacryma-jobi fell under the 4A asymmetric category of Stebbins classification. Chromosome number and karyomorphology of C. lacryma-jobi var. puellarum are reported for the first time.

The genus Ctenodon was recently reestablished to include the Ochopodium section of Aeschynomene. This genus is composed of 78 species and infraspecific taxa that are found in the Neotropics. However, quantitative cytogenetic information is only available for three of these species. To describe the chromosome morphology of Ctenodon elegans, a species with a wide distribution in tropical America, an air-drying (splash) method and Giemsa staining were used. Chromosome complements in metaphase and prometaphase showed a diploid chromosome number of 2n=20, which is common in the dalbergioid clade. The karyotype formula obtained, 9m+1sm, is like that of another cogeneric species. However, other cytogenetic parameters differ from those of previously studied species. These results confirm a wide chromosome diversity in Ctenodon, including differences in the arrangement of satellite (SAT) chromosomes considered nucleolar organizer region (NOR) chromosomes within the karyotype. The study also highlights that total and average chromosome size are not the most important parameters in the comparative cytogenetics of the genus. Other parameters, such as karyotype symmetry, must be considered to advance our understanding of chromosome evolution in dalbergioids.

The purpose of this study was to record gametophytic chromosome numbers for 30 species belonging to the family Lamiaceae from the regions of North-West India. During the investigations the accession of Stachys sericea was recorded to bear a gametophytic chromosome number of n=16; a new chromosome number for the taxa at the global level. Gametophytic chromosome numbers in three accessions of Mentha arvensis, Nepeta nervosa, and Scutellaria galericulata were recorded as n=12, n=7, and n=16 respectively for the first time from India. The chromosome numbers for 47 accessions belonging to 26 species were rereported for the taxa studied. The present study contributed four new chromosome numbers for the Indian taxa of Lamiaceae.

This study aimed to investigate the somatic chromosome numbers and morphometric properties of chromosomes in five endemic species of the genus Bellevalia Lapeyr. (Asparagaceae) from Turkey. The examined taxa are B. behcetii Pınar, Eroğlu & Fidan, B. koyuncui Karabacak & Yıldırım, B. pseudolongipes Karabacak & Yıldırım, B. sasonii Fidan, and B. vuralii B.Şahin & Aslan. Karyological techniques were employed to assess the chromosome number and morphology of the species. The genus Bellevalia is by a basic chromosome number x=4. Chromosome numbers of the species were determined B. behcetii, B. koyuncui, B. pseudolongipes, and B. sasonii 2n=2x=8, while B. vuralii 2n=4x=16, was determined. Satellites were observed in two species; B. behcetii and B. vuralii. Using the Stebbins classification system, species were categorized as class 3A. Additionally, various parameters such as chromosome number, total chromosome length, relative length, arm ratio, centromere index, and centromere states, karyotype asymmetry values, and karyotype formula were determined. Notably, this study marks the first time that chromosome numbers of B. sasonii have been defined, contributing valuable new data to the systematics of these species.