Experimental Researches on Carcinogenesis or Tumorigenicity of MDCK Canine Kidney Cell(CKC) Lines and Analysis of Their Chromosome Karyotypes

The chromosomal number variations & structural aberrations of the MDCK cell line, primary feline or canine kidney cell(FKC or CKC) and Hela cell line were investigated and their karyotypes of conventional chromosome bands were analyzed. The carcinogenesis or tumorigenicity testing of these cell lines in about 232 nude mice and for colony formation in soft agarose and for haemagglutination under different concentration of plant lectins of these cells were carried out. Under the prerequisite that the incidence of cancer or tumor in negative-control nude mice inoculated subcutaneously with primary feline or canine kidney cell cultures purified in vitro at passage 3 was 0 (0/22) and 0 (0/10), respectively. The incidence of the progressively-growing malignant tumor(MT) in positive-control nude mice inoculated subcutaneously with Hela cell cultures of KB, X, or NM20/X strain was 10/10, 25/25 and 5/51, respectively. The results showed that the incidence of tumor in nude mice with tetraploid YA strain of MDCK cell during 20 - 45 passages, with hy-podiploid JB strain of MDCK cell on passage 25, with di-and hypoploid JC strain of MDCK cell during 2-15 passages or with hypoploid M strain of MDCK cell during 9 - 27 passages was 28/58, 1/5, 4/18 and 0/31, respectively. The chromosomal analysis results showed that the ratio of difference in the rate of modal chromosome number between high(mcs+ n) and lowest (mcs) passages was not more than 5% - 15% and the structure aberrations was generally 0 - 3% . These results proved that the genetic characteristics of chromosomal number of cell lines determines their tumorigenicity, but it is species-specific. MDCK line has tumorigenicity no matter what its chromosome karyotype is, at least it has very low tumorigenicity even when its modal chromosome number is hypoploid. The repeatedly frozen, thawed and split controls of tumorigenicity-positive cell lines(X strain of Hela, M strain of BHK-21, JA strain of Vero, YA strain of MDCK) have much lower tumorigenicity or are even non-carcinogenesis, and the repeatedly frozen, thawed and split controls of very low tumorigenicity cell lines (M or JC strain of MDCK) are certainly non-carcinogenic and never have increased tumorigenicity. It is thus evident that MDCK cell of M, JB or JC strain can be approved as substrate for the preparation of attenuated viral vaccines, but MDCK cell of YA strain can not be approved as substrate for the preparation of attenuated viral vaccines. In summary, all strains of MDCK cell line have tunorigenicity, at least have low tumor igencity , never have non-cancinogenic MDCK, but very low tumorigenicity MDCK cell strains can certainly be used for the approval production of canine viral vaccines if the DNA content in viral cell cultures was remarkably decreased through conventional means in manufacturing process. Therefore, the master cell stock and working cell bank of MDCK line used for vaccine manufacture were established in China, which are free of infectious agents, and described with respect to cytogenetic characteristics and tumorigenicity.Tests showed that there were correlations among cell line chromosome number variations, anchorage independence in soft a-garose, haemagglutination under plant lectins, and tumor-forming ability in nude mice, thus all the in vitro tests are economic, simple and reliable means for monitoring the tumor-forming ability of MDCK line in nude mice.

Karyotypes of three species of the marine Veneroida molluscs

The karyotypes of three species of marine Veneroida molluscs, Solen grandis Dunker, Saxidomus purpuratus Sowerby and Mactra chinensis Philippi were studied by using the adult gill tissues. The chromosomes were-prepared through injecting phytohemagglutinin (PHA) and colchicine, hypotonic treatment, chopping air-dry, and squashing technology. The results show that the diploid chromosome numbers of the three Veneroida species are the same as 2n = 38. The karyotype of Solen grandis is 26m + 6sm + 2st + 4t, NF = 70, the karyotype of Saxidomus purpuratus is 32m + 2sm + 4st/t, NF = 72, and the karyotype of Mactra chinensis is 20m + 16sm + 2st/t, NF = 74. Satellite and sex chromosome were not found among the chromosomes of three species.

Karyotypes of field mice of the genus Apodemus (Mammalia： Rodentia) from China

Karyotypes of four Chinese species of field mice of the genus Apodemus were examined,including Apodemus chevrieri （diploid chromosome number,2n=48,fundamental number of autosomal arms,FNa=56）,A.draco （2n=48,FNa=48）,A.ilex （2n=48,FNa=48）,and A.latronum （2n=48,FNa=48）.Karyotypes of A.chevrieri,A.draco,and A.ilex are reported here for the first time,providing useful information for their species taxonomy.Determining the karyotypes of all species of Apodemus in Asia,both in this and previous studies,provides a solid overview of the chromosome evolution and species differentiation of the genus in East Asia.In addition to allopatric speciation,chromosome rearrangements likely played an important role in the formation of the four Apodemus species groups as well as speciation within each group in East Asia.For example,increased centromeric heterochromatin in A.latronum may have contributed to the post-mating reproductive isolation from the A.draco-A.ilex-A.semotus clade.

Karyotypes of nineteen species of Asteraceae in the Hengduan Mountains and adjacent regions

The Hengduan Mountains region is a biodiversity hotspot. In this study, we report the karyotypes of 19 species(21 populations) of Asteraceae from this region, 14 of which are reported for the first time. We also examined polyploidy in Asteraceae plants and summarized karyotype data in the literature for 69 congeneric taxa. In these genera, there were five different ploidy levels in the region, though the most dominant was diploid(73.08%). There is no direct evidence that ploidy level and karyotype asymmetry are associated with the distribution of recorded Asteraceae species from the Hengduan Mountains. This suggests that polyploidy(26.92%) may not play an important role in the evolutionary history of these plants, even though, among these genera, the ratio of paleopolyploidy was high(46.15%).

Chromosomal Karyotypes of Medicinal Plant Gynura medica

[ Objective] This study aimed at investigating the chromosomal characteristics and karyotypes of Gynura medica. [ Method ] Stem tips of G. medica seedlings were taken every 20 min from 6：30 to 10：30 am, and then were treated and squashed. The slices were observed under a microscope for investigating the chromosomal number and karyotypes of the cells in metaphase in which the chromosomes were well dispersed. [ Result] In the total 102 stem tip cells in meta- phase, 96.08% of cells were with 20 chromosomes, and 3.92% of cells were with 40 chromosomes. Optimal time for sampling was from 7：50 to 9：30 am, when more cells were in metaphase. [Conclusion] C. medica is the diploid plant with 20 chromosomes. Karyotype analysis gets formula 2n = 2x = 20m, and all 10 pairs of chromosomes belong to type 1A. The article reporls the chromosomes characteristics of G. rnedica firstly.

A Study on Karyotypes and Ag-NORs of Odontobutis potamophila

In order to obtain cytogenetic data of Odontobutis potamophila,head-kidney cells were collected as experimental materials to prepare chromosome specimen. The karyotypes of O. potamophila and the distribution and amount of transcriptionally active nucleolar organizer regions on chromosomes were analyzed by Giemsa staining and Ag-NORs. The results showed that the number of diploid chromosomes of O. potamophila was 44; the genome of O. potamophila was composed of 44 telocentric chromosomes; the karyotype formula was 2 n = 44 t,NF = 44; Ag-NORs were found in the paracentromeric region of chromosome. The results may lay the foundation for revealing the genetic pattern and chromosomal evolution of O. potamophila and contribute to further genetic breeding of O. potamophila.

A Comparative Study of the Karyotypes from Four Egg-type Fowl Breeds

By adopting the method based on colchicine-hypotonic-air drying technique with bone marrow cells, the paper presents the chromosome of four egg-type fowl breeds. The diploid chromosome 2n=78, chromosomal morphology are very similar and sex chromosome type are ZZ (♂) and ZW(♀) in four egg-type fowl breeds. According to standard of Leven in 1964, the euchromosome and sex chromosome of four breeds are measured and compared in relative length arm ratio and centromere index of each chromosome including all the microchromosome. The morphology of these chromosome is described as follows: pair1, 2, 8 and ZW are metacentric, pair 4 and 6 are submetacentric, and the rest is telocentric.

Karyotypes of parasitic Hymenoptera： Diversity, evolution and taxonomic significance

Haploid chromosome numbers （n） of parasitic Hymenoptera （= traditional Parasitica ＋ Chrysidoidea） vary from 2 to 23. However, this range can be subdivided into three intervals with n = 14-23 （less derived parasitic wasps, e.g., some Ichneumonidae and Braconidae as well as Gasteruptiidae）, 8-13 （many other parasitic Hymenoptera） and 2-7 （Dryinidae, the majority of Chalcidoidea and some advanced Braconidae, e.g. Aphidiinae）. The symmetric karyotype with a relatively high chromosome number （n -- 14-17） and the prevalence of biarmed chromosomes must be considered as a groundplan feature of parasitic Hymenoptera. Independent reductions of chromosome numbers （n ≤ 10-11） occurred in some groups of the superfamily Ichneumonoidea as well as in the common ancestor of the Proctotrupoidea sensu lato, Ceraphronoidea, Cynipoidea and Chalcidoidea. Further mul- tiple decreases in chromosome numbers （n ≤ 4-6） took place in some Braconidae, various lineages of the superfamily Chalcidoidea as well as in the family Dryinidae. Two main trends prevailed in the karyotype evolution of parasitic wasps： the reduction of chromosome numbers （mainly due to tandem fusions and less frequently due to centric ones） and karyotypic dissymmetrization （through an increase in size differentiation of chromosomes and/or in the share of acrocentrics in a chromosome set）. Although karyotypic features of parasitic Hymenoptera can be used for solving taxonomic problems at various levels, this method is the most effective at the species level.

A likely paleo-autotetraploidization event shaped the high conservation of Nyssaceae genome

Scientific knowledge about the ancestral genome of core eudicot plant kingdom can potentially have profound impacts on both basic and applied research,including evolution,genetics,genomics,ecology,agriculture,forestry,and global climate.To investigate which plant conserves best the core eudicots common ancestor genome,we compared Arcto-Tertiary relict Nyssaceae and 30 other eudicot plant families.The genomes of Davidia involucrata(a known living fossil),Camptotheca acuminata and Nyssa sinensis,one per existent genus of Nyssaceae,were performed comparative genomic analysis.We found that Nyssaceae originated from a single Nyssaceae common tetraploidization event(NCT)-autotetraploidization 28-31 Mya after the core eudicot common hexaploidization(ECH).We identified Nyssaceae orthologous and paralogous genes,determined its chromosomal evolutionary trajectory,and reconstructed the Nyssaceae most recent ancestor genome.D.involucrata genome contained the entire seven paleochromosomes and 17 ECH-generated eudicot common ancestor chromosomes and was the slowest in mutation among the analyzed 42 species of 31 plant families.Combing both its high retention of paleochromosomes and its low mutation rate,D.involucrata provides the best case in conservation of the core eudicot paleogenome.

Repeated pregnancy losses with multiple aneuploidies and major genomic imbalance:A case report

Rationale:If one of the partners is having balanced autosomal translocation,it is usually observed that the offspring inherit either normal chromosomes,balanced translocation identical to one of the parent or unbalanced chromosomal rearrangements of the same parental chromosome having translocation.Concern:A unique case presented with history of 8 miscarriages for genetic counseling.The last abortus material evaluation showed monosomy of chromosome X(Turner syndrome)in all the analyzed cells.There was a history of infertility and also repeated second trimester abortions on the paternal side.On the maternal side,there was a history of intellectual disability.Diagnose:History of repeated abnormal pregnancy outcomes.Wife’s karyotype is normal;however,husband shows translocation between chromosome 4 and 22.Intervention:Peripheral blood sample around 3 mL was collected for karyotype.Embryo biopsy was done and DNA was extracted and processed for whole exome sequencing.Outcomes:Wife’s karyotype is normal and husband has translocation between chromosome 4 and 22.Surprisingly,the entire pregnancy outcome including embryo screening has different,complete or partial aneuploidies of chromosomes other than chromosome 4 and 22.Main lesson:Though the translocation in one of the parent is balanced,we have to think beyond traditional ways for evaluating a couple with repeated pregnancy loss as we cannot predict the errors at cell division.Option of in vitro fertilization and preimplantation genetic diagnosis in couples having balanced translocations should be discussed so that early intervention can prevent the agony of pregnancy loss.

Clinical manifestations and the prenatal diagnosis of trisomy 7 mosaicism:Two case reports

BACKGROUND The clinical manifestations of trisomy 7 mosaicism are diverse and nonspecific,so prenatal diagnosis is very difficult.CASE SUMMARY Two pregnant women with abnormal prenatal screening results were included.One was a 22-year-old woman(G1P0).At 31st week of gestation,ultrasound revealed that the posterior horn of the left lateral ventricle was 10 mm and the right renal pelvis had a separation of 7 mm.The other pregnant woman was 33 years old(G2P1L1A0),and her fetus was found to have a cardiac malformation at the 24th week of gestation.Copy number variation sequencing,whole-exome sequencing and karyotype analysis were carried out after amniocentesis,and both fetuses were diagnosed with trisomy 7 mosaicism.After parental counseling,one woman continued the pregnancy,and the other woman terminated the pregnancy.CONCLUSION In trisomy 7 mosaicism,the low proportion of trisomy does not lead to abortion,but can result in abnormal fetal development,which can be detected via ultrasound.Therefore,clinicians need to pay more attention to various aspects of fetal growth and development,combining with imaging,cellular,molecular genetics and other methods to perform comprehensive evaluations of fetuses to provide more reliable genetic counseling for pregnant women.

WGDI:A user-friendly toolkit for evolutionary analyses of whole-genome duplications and ancestral karyotypes

Evidence of whole-genome duplications(WGDs)and subsequent karyotype changes has been detected in most major lineages of living organisms on Earth.To clarify the complex resulting multi-layered patterns of gene collinearity in genome analyses,there is a need for convenient and accurate toolkits.To meet this need,we developed WGDI(Whole-Genome Duplication Integrated analysis),a Python-based command-line tool that facilitates comprehensive analysis of recursive polyploidization events and cross-species genome alignments.WGDI supports three main workflows(polyploid inference,hierarchical inference of genomic homology,and ancestral chromosome karyotyping)that can improve the detection of WGD and characterization of WGD-related events based on high-quality chromosome-level genomes.Significantly,it can extract complete synteny blocks and facilitate reconstruction of detailed karyotype evolution.This toolkit is freely available at GitHub(https://github.com/SunPengChuan/wgdi).As an example of its application,WGDI convincingly clarified karyotype evolution in Aquilegia coerulea and Vitis vinifera following WGDs and rejected the hypothesis that Aquilegia contributed as a parental lineage to the allopolyploid origin of core dicots.

Karyotypes of three shrew species(Soriculus nigrescens,Episoriculus caudatus and Episoriculus sacratus)from Nepal

The karyotypes of three shrew species(Mammalia,Soricomorpha,Soricidae)from Nepal were examined for the first time.Based on the karyotypes and overall differences in skull size,the current Episoriculus caudatus appeared to include two distinct species:the larger E.caudatus and the smaller Episoriculus sacratus.Episoriculus sacratus has three subspecies,E.s.soluensis in Nepal and Sikkim,E.s.umbrinus in Assam,Myanmar and the Yunnan Province of China,and E.s.sacratus in the Sichuan Province of China.Soriculus nigrescens had a diploid chromosome number(2n)and fundamental number(FN),including two X chromosomes,of 64 and 92,respectively,consisting of 11 metacentric or submetacentric,two subtelocentric and 18 acrocentric pairs of autosomes,a metacentric X and an acrocentric Y chromosome.Episoriculus sacratus soluensis had 2n=74 and FN=126,consisting of 12 metacentric or submetacentric,13 subtelocentric and 11 acrocentric pairs of autosomes,a submetacentric X and an acrocentric Y chromosome.Episoriculus caudatus had 2n=60 and FN=118,consisting of 19 metacentric or submetacentric,nine subtelocentric and one acrocentric pair of autosomes,a subtelocentric X and an acrocentric Y chromosome.The karyotypes of these three species are characterized by their large 2n and FN values compared with other Soricidae.

Comparative analysis of the morphology,karyotypes and biochemical composition of muscle in Siniperca chuatsi,Siniperca scherzeri and the F1 hybrid(S.chuatsi♀×S.scherzeri♂)

Combining morphological comparison with karyotyping can make a more accurate and comprehensive study of mandarin fish(Siniperca spp.)and hybrid progenies.In recent years,the domestication of hybrid mandarin fish has become a hot spot in China,and it is essential to evaluate the nutritional value of the fish after food conversion.In this study,the F1 hybrid(S.chuatsi♀×S.scherzeri♂)were fed with artificial feed for five months.Afterwards,we studied the morphology,karyotypes,and biochemical composition of muscle in the F1 hybrid and its parents.The morphological results showed that total length and body height of the F1 hybrid appear to derive more from S.chuatsi than S.scherzeri.The DNA ploidy and karyotype results indicated that the F1 hybrid have a diploid chromosome number(2n=48)and the same karyotypes(2n=4sm+14th+30t,NF=52)with its parents,suggesting that the chromosome of the mandarin fish has convergence in the process of evolution.The results of biochemical composition of muscle showed that there were no significant difference in other nutritional indicators(P>0.05),except the Gly(glycine)content of the F1 hybrid was significantly higher than that of S.chuatsi(P<0.05)under the experimental feeding regime,suggesting that the nutritional value of the F1 hybrid with artificial feeding culture is also higher.The study is expected to provide a reference for further research on the domestication,classification,chromosomes,and nutritional requirements of mandarin fish.

High chromosomal evolutionary dynamics in sleeper gobies(Eleotridae)and notes on disruptive biological factors in Gobiiformes karyotypes(Osteichthyes,Teleostei)

The order Gobiiformes is made up of more than 2200 species,representing one of the most diverse groups among teleost fishes.The biological causes for the tachytelic karyotype evolution of the gobies have not yet been fully studied.Here we expanded cytogenetic data for the Eleotridae family,analyzing the neotropical species Dormitator maculatus,Eleotris pisonis,Erotelis smaragdus,and Guavina guavina.In addition,a meta-analytical approach was followed for elucidating the karyotype diversification versus biological aspects(habitat and egg type)of the Gobiiformes.The species E.smaragdus and E.pisonis present 2n=46 acrocentric chromosomes(NF=46),D.maculatus 2n=46(36sm+4st+6a;NF=86),and G.guavina,the most divergent karyotype,with 2n=52 acrocentric chromosomes(NF=52).Besides numeric and structural diversification in the karyotypes,the mapping of rDNAs and microsatellites also showed noticeable numerical and positional variation,supporting the high chromosomal evolutionary dynamism of these species.In Gobiiformes,karyotype patterns which are more divergent from the basal karyotype(2n=46a)are associated with characteristics less effective to dispersion,such as the benthic habit.These adaptive characteristics,connected with the organization of the repetitive DNA content in the chromosomes,likely play a synergistic role in the remarkable karyotype diversification of this group.

A likely autotetraploidization event shaped the Chinese mahogany(Toona sinensis)genome

Chinese mahogany(Toona sinensis) is of considerable medical and economic importance, and its genome has been deciphered. However, the process underlying its polyploidy is unclear, and the chromosomal evolutionary trajectory is poorly understood. Here, by reanalysing the T.sinensis genome, we found evidence of a tetraploidization event(T. sinensis special tetraploidization, TST) that occurred approximately 15-17 million years ago(MYA) after the core eudicot-common hexaploidization(ECH or gamma) event. We characterized the synonymous nucleotide substitution rates(Ks values) of collinear genes and found that T. sinensis genes affected by the TST evolve at a slower rate than Acer yangbiense genes. Furthermore, we identified homologous genes related to polyploidization and speciation and constructed multiple alignments with different reference genomes. Notably, the significant balance of gene retention and loss characterized in the two TST-derived subgenomes suggests an autopolyploid nature of the TST. Moreover, we deduced the chromosomal karyotypes of the two subgenomes and identified 7chromosomal fusions that have shaped the T. sinensis genome;more information is available on a newly constructed karyotype platform(http://www.cgrpoee.top/Toona_sinensis/index.html). The T. sinensis genome preserves the ancestral chromosome structure of dicotyledons well and could serve as a good reference for understanding genomic changes in other Meliaceae and Sapindales plants. In addition, we verified that tandem duplication and the ECH have promoted the expansion of terpene synthase(TPS) genes;conversely, the TST seems to have inhibited expansion of these genes. This present effort has clarified the polyploidy events of the T. sinensis genome, filled gaps in the history of karyotype evolution, and laid a solid foundation for further genomic studies in the Meliaceae research community and beyond.

Unique Roberts syndrome with bilateral congenital glaucoma: A case report

BACKGROUND Congenital glaucoma associated with Roberts syndrome(RS)is an unusual and unique condition.No previous report describes this association.A multidisciplinary approach including molecular studies were conducted to reach the final diagnosis.CASE SUMMARY We present a rare case of a 1-wk-old male with RS associated with bilateral congenital glaucoma,left ectopic kidney,and left-hand rudimentary digits.A comprehensive approach was applied by which bilateral non-penetrating glaucoma surgery was performed with good control of intraocular pressure for more than 6 mo.Cytogenetic and molecular testing were conducted and revealed normal measurements.CONCLUSION This report described a case of a male baby with clinical features of RS but with a negative molecular analysis,presenting with left-hand rudimentary digits,bilateral congenital glaucoma,and left ectopic kidney.To the best of our knowledge,this is the first case reported with phocomelia,bilateral congenital glaucoma,and unilateral ectopic kidney.

Confusing finding of quantitative fluorescent polymerase chain reaction analysis in invasive prenatal genetic diagnosis:A case report

BACKGROUND Quantitative fluorescent polymerase chain reaction(QF-PCR)is a rapid prenatal diagnostic method for abnormalities on chromosomes 21,18,and 13 and sex chromosomal aneuploidy.However,the value of QF-PCR in diagnosing chromosomal structural abnormalities is limited.In this article,we report a confusing QF-PCR finding in a pregnant woman who underwent amniocentesis.CASE SUMMARY The short tandem repeat marker AMXY(Xp22.2/Yp11.2)located on the sex chromosome exhibited a trisomic biallelic pattern,indicating that the karyotype of the fetus might be 47,XYY.Chromosome analysis performed on cultured amniocytes showed a normal male karyotype of the fetus.Copy number variation sequencing confirmed a 500 kb duplication at Yp11.2-Yp11.2(chrY:6610001_7110000)and a 250 kb duplication at Yp11.2-Yp11.2(chrY:7110001_7360000).CONCLUSION In conclusion,the comprehensive application of different methods could achieve a higher detection rate and accuracy for the prenatal diagnosis of chromosomal disorders through chromosomal testing.

Correlation between Reasons for Prescription and Karyotype Results in Patients Referred for Suspected Chromosomal Abnormalities

Karyotype prescription is based on clinical signs (or reasons for karyotype prescription) which are phenotypic manifestations associated with chromosomal abnormalities. The aim of this study was to establish a correspondence between karyotype indications and their results in patients. This was a retrospective study that was carried out in the Histology-Embryology-Cytogenetics laboratory of the University Hospital of Cocody-Abidjan from 2014 to 2019. 58 patient files were identified and included the indication or reason for prescribing a constitutional karyotype and the biological result obtained. An individual data sheet was used to collect the data. 17 reasons for prescription were identified and divided into 2 groups. Sexual ambiguity was the most frequent reason (29.3%). The first group (G1) represented the 10 reasons for which the karyotype results were normal. The second group (G2) corresponded of the 7 motives with normal or abnormal karyotype results. Several anomalies were listed according to these reasons: inversions, mosaics (anomalies of number and structure) and trisomy 21. The last was the most frequent chromosomal anomaly (69.24%). It was found in several reasons for karyotype prescription: malformations, neurological disorders, suspected trisomy and cardiac pathology. Several factors could explain these results, among which are the limits of the karyotype and the non-genetic causes that can induce these abnormal phenotypes. Complementary examinations to the karyotype are molecular cytogenetic techniques, notably fluorescence in situ hybridization (FISH) and array comparative genomic hybridization (Array-CGH).

烟台绵枣儿的核型研究(英文)

[Objective] The aim of this study was to investigate the chromosome number and the karyotype of Scilla scilloides in Yantai.[Method]Root tips of Scilla scilloides were pretreated by 8-hydroxyquinoline,then fixed,dissociated and stained for slice production.The chromosome number was analyzed by microscopic examination,and then cells with good chromosomal morphology and dispersal chromosome were studied by microscopic photos.[Result]The somatic chromosome number of Scilla scilloides in Yantai was 2n=16+1Bs,while the karyotype formula was K(2n)=2x=16+1Bs=6m+4sm(2SAT)+4st+2t+1Bs and the karyotype classification was "3B" type.[Conclusion]Karyotype comparison,division of cell type and evolution of Scilla scilloides in Yantai are discussed,which provides basis for cytogenetics,evolutionary genetics,modern taxonomy and genetic breeding.