• Proceedings of the Korean Aquaculture Society Conference
• /
• 2003.10a
• /
• pp.38-38
• /
• 2003

Blocking the first mitotic cleavage of the zygote is a key tool for chromosome-set manipulations in fish. We developed an improved method for inducing tetraploidy by blocking the mitosis with a combination of heat shock at 40.5$^{\circ}C$ for 1, 2 or 3 min followed by cold shock at $1.5^{\circ}C$ for 30, 45 or 60 min. When applied during the first cleavage metaphase of mud loach (Misgurnus mizolepis) zygotes, the optimal combination was heat for 2 min followed by cold for 45 min. At 1 month, the frequency of 4N survivors and the yield from total eggs fertilized was 55.7% and 14.4%, respectively, compared to heat shock alone with 20.0% efficiency and 3.6% yield. The effectiveness of the procedure was confirmed by diploid mitotic gynogenesis using transgenic markers. The overall yield of homozygous diploids, 34.0%, was better than that for single heat shock, 17.3%. The tetraploids and homozygous diploids had higher early mortality than normal diploid controls. However at 1 month, the viability of the tetraploids was the same as normal diploids. For gynogenetic diploids, the survival was similar to normal diploids after 3 months. The high efficiency of this new protocol extends the opportunity to study polyploidy in basic and applied research.

• Korean Journal of Plant Resources
• /
• v.28 no.5
• /
• pp.656-664
• /
• 2015

To produce high quality watermelon, three tetraploid watermelon breeding lines (‘SA03-1’, ‘SA06-1’ and ‘SB01-1’) were developed by treatment with different chromosome doubling reagents. To identify the optimal tetraploid inductive conditions, the three watermelon breeding lines were selected by counting the number of doubled chloroplasts in guard cells. Tetraploid induction rates differed depending on the genotypes and treatment with doubling reagents. However, the highest induction rate occurred with 1.0% colchicine (82.2%). These putative tetraploid lines were re-confirmed for ploidy using flow cytometric analysis and chromosome counting. The internode length of the tetraploid breeding lines was different when the leaf size was larger in all three tetraploid lines compared to their diploids. The fruit weight of the tetraploid fruits for ‘SA03-1’ and ‘SB01-1’ was lower than for their diploid, and the rind thickness and total sugar content (°Brix) of tetraploid SB01-1 were significantly different from those of its diploid. Tetraploid lines were sterile, yielded a lower number of seeds per fruit for ‘SA03-1’ (21), ‘SA06-1’ (62), and ‘SB01-1’ (34.7), and the seeds were larger and thicker than those of their diploids. These tetraploid breeding results will be useful for breeding new seedless watermelon cultivars.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.273-273
• /
• 2017

Polyploidy has opened a new horizon for selection to sculpt a variety of new gene functions, traits, and lineages. The aim of this study was to investigate the efficacy of the colchicine concentration, temporal changes, and suitable material for inducing effective tetraploid plants of Codonopsis lanceolata. A total of 180 individuals from 16 treatment groups were germinated, and exposed to different concentrations of Colchicine. The plant height of the diploid (18.1 cm) was slightly shorter than that of the tetraploid (13.4 cm). The fresh weight of the main root in the diploid (0.5 g) was 4-fold higher than the tetraploid (2.2 g). The colchicine-treated plant regeneration rate in C. lanceolata was decreased at the elevated concentration of colchicine. A total of 126 individual plants were regenerated in the entire treatment group and tetraploid (2n=4x=32) plants were obtained. In particular, 5 individuals of the tetraploid plant were induced in the 0.05% colchicine for 6h, which is a higher rate (29.4%) than other regenerated plants. As in the seed treatment result, the plant height of the diploid was significantly higher (10.4 cm) than tetraploid. The root length of the tetraploid (10.1 cm) was longer than the diploid, and the root was also thicker. Taken together, the results obtained from the present study may be helpful for the efficient recovery of such polyploid plants through the in vitro application of colchicine, and may improve the productivity and breeding of C. lanceolata.

• Plant Biotechnology Reports
• /
• v.5 no.3
• /
• pp.265-271
• /
• 2011

The cultivated potato as well as its tuber-bearing relatives are considered model plants for cell and tissue culture, and therefore for exploiting the genetic variation induced by in vitro culture. The association between molecular stability and tissue culture in different genetic backgrounds and ploidy levels has already been explored. However, it still remains to be ascertained whether somaclonal variation differs between callus-derived chromosome-doubled and undoubled regenerants. Our research aimed at investigating, through amplified fragment length polymorphism (AFLP) markers, the genetic changes in marker-banding patterns of diploid and tetraploid regenerants obtained from one clone each of Solanum bulbocastanum Dunal and S. cardiophyllum Lindl (both 2n = 2x = 24) and tetraploids from cultivated S. tuberosum L. (2n = 4x = 48). Pairwise comparisons between the banding patterns of regenerants and parents allowed detecting considerable changes associated to in vitro culture both at diploid and tetraploid level. The percentages of polymorphic bands between diploid and tetraploid regenerants were, respectively, 57 and 69% in S. bulbocastanum and 58 and 63% in S. cardiophyllum. On average, the frequencies of lost parental fragments in regenerants were significantly higher than novel bands both in S. bulbocastanum (48 vs. 22%) and S. tuberosum (36 vs. 18%) regenerants. By contrast, in S. cardiophyllum, a similar incidence of the two events was detected (32 vs. 29%). Our results revealed that structural changes after tissue culture process strongly affected the genome of the species studied, but diploid and tetraploids regenerated plants responded equally.

• Clinical and Experimental Reproductive Medicine
• /
• v.24 no.3
• /
• pp.319-324
• /
• 1997

Despite the direct placement of sperm within the oocyte, fertilization failure still occurs after ICSI. This study was accomplished to analyze the chromosomes in oocytes failed to fertilize after ICSI comparing to oocytes failed to fertilize by conventional in vitro insemination. Seventy-four ICSI cycles and 122 conventional IVF cycles were included in analysis. Included unfertilized oocytes were from 74 patients (mean age = $32.7{\pm}3.7$). Ninety-three oocytes were informative and 83 oocytes were legible for cytogenetic analysis. Sixty-two oocytes out of 83 (74.7%) had normal chroruosomes, while 15 (18.1%) were hypoploidy, 6 (7.2%) were hyperploidy. Eighteen oocytes out of 93 (17.6%) were premature chromosome condensation (PCC). Two hundred ninety-four unfertilized oocytes after conventional insemination were subjected to chromosomal analysis and 180 oocytes were legible for analysis. One hundred thirty-two oocytes out of 180 (73.3%) were normal, while 22 (12.2%) were hypoploidy, 20 (11.1%) were hyperploidy, and 6 (3.3%) were polyploidy. Twenty-two oocytes (12.2%) were PCC. There was no difference in chromosomes between oocytes that failed to fertilize after ICSI or conventional insemination. High PCC rates in fertilization-failed oocytes suggest that oocytes maturity is another important factor in achieving successful fertilization.

• FLOWER RESEARCH JOURNAL
• /
• v.18 no.4
• /
• pp.284-290
• /
• 2010

This study was carried out to breed a self-compatible variety of Tiger Lily from the seedlings originated from Chinju city, Gyeongsangnam-do. The morphological characteristics, ploidy, and the resistance of seedlings to virus infection were investigated. A progeny test was also conducted to examine whether the propagated progenies had the same characteristics as the mother plant. The self-compatible diploid lily variety developed in this study showed a tall type like native triploid lily, Lilium tigrinum, and bulbils were formed on both lily varieties. The morphological characteristics of the flowers and leaves were not much different between the varieties, while the size of the bulbils and bulbs showed significant differences. The percentage of seed generation by self-pollination was 72.6% for the self-compatible variety, while there was no seed generated for native triploid lily. The number of chromosome was 2n = 26 (x = 13, diploid) for the self-compatible variety, while 2n = 39 (x = 13, triploid) in native lily variety. The progenies of the self-compatible diploid lily variety showed the same characteristics as those of its mother plant in morphology, seed germination, and polyploidy. The mother plant of the self-compatible diploid lily variety showed 58% pollen germination and the 2-year-old and 3-year-old progenies showed similar germination percentages. The pollen grains of Korean native triploid lily, however, never germinated.

• Journal of Plant Biotechnology
• /
• v.43 no.1
• /
• pp.12-20
• /
• 2016

Advances in DNA sequencing technologies have contributed to revolutionary understanding of many fundamental biological processes. With unprecedented cost-effective and high-throughput sequencing, a single laboratory can afford to de novo sequence the whole genome for species of interest. In addition, population genetic studies have been remarkably accelerated by numerous molecular markers identified from unbiased genome-wide sequences of population samples. As sequencing technologies have evolved very rapidly, acquiring appropriate individual plants or populations is a major bottleneck in plant research considering the complex nature of plant genome, such as heterozygosity, repetitiveness, and polyploidy. This challenge could be overcome by the old but effective method known as haploid induction. Haploid plants containing half of their sporophytic chromosomes can be rapidly generated mainly by culturing gametophytic cells such as ovules or pollens. Subsequent chromosome doubling in haploid plants can generate stable doubled haploid (DH) with perfect homozygosity. Here, classical methodology to generate and identify haploid plants or DH are summarized. In addition, haploid induction by epigenetic regulation of centromeric histone is explained. Furthermore, the utilization of haploid plant in the genomics era is discussed in the aspect of genome sequencing project and population genetic studies.

• Journal of Genetic Medicine
• /
• v.8 no.1
• /
• pp.44-52
• /
• 2011

Purpose: Cytogenetic analysis of spontaneous abortions (SABs) provides valuable information to establish the causes of fetal loss, information that is essential to provide accurate reproductive and genetic counseling couples. Such analysis also provides information on the frequencies and types of chromosomal abnormalities and associated risks of recurrence. However, there have only been a few reports of chromosomal abnormalities in small samples of SABs in the Korean population. Here, we report the incidence and spectrum of chromosomal abnormalities for cases of 470 SAB in Korea. Material and Methods: Between 2005 and 2010, a total of 470 products of conception (POC) resulting from SABs were submitted to our laboratory for cytogenetic analysis from various medical sites in Korea. The incidences and types of specific chromosomal abnormalities were determined. The abnormalities were distinguished by gestational age at the time of SAB and by maternal age. Results: The frequency of chromosomal abnormalities in POCs was 54.3% (255/470), including 228 (89.3%) numerical and 27 (10.7%: 3 balanced and 24 unbalanced) structural abnormalities. Among the numerical abnormalities, trisomy was predominant (67.0%), followed by monosomy X (12.5%), polyploidy (8.2%), triple X (0.8%), and autosomal monosomy (0.8%). The overall sex ratio (male: female) among the 470 POCs with normal and abnormal karyotypes were 0.58 and 0.65, respectively. Trisomies were identified for each autosome, with the exceptions of 1, 3, and 19. Among the 171 autosomal trisomies, trisomy 16 was the most common (19.9%), followed by trisomy 22 (13.5%), trisomy 21 (12.3 %), trisomy 15 (9.9%), and trisomies 18 and 13 (5.3%). The frequency of chromosomal abnormalities decreased with gestational age and increased with maternal age, but only because of increases in trisomies and complex abnormalities. Conclusions: We have presented a large collection of cytogenetic data for SABs collected during the past 6 years and provided a database for prenatal genetic counseling of parents who have experienced SABs in Korea.