26 public questions tagged with this topic.
Somatic hybridization involves the fusion of isolated protoplasts from different plant species to form hybrid lls. This follows from NCERT principle where relation explains outcome clearly for students.
Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Biology - Zoology portion covering relevant system and function, Topic: Structural organization and physiology.
Somatic hybridization involves the fusion of protoplasts from different species to form hybrid plants with combined traits. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.
Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, ph
Somatic hybridization involves the fusion of protoplasts from different plant species to form hybrid plants with combined traits. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Biology - Zoology portion covering relevant system and function.
Floral meristem identity genes LEAFY, APETALA1, CAULIFLOWER act as master developmental switches converting indeterminate shoot apical meristem into determinate floral meristem upon flowering induction via FT-FD florigen complex integrating photoperiod, vernalization, autonomous, and gibberellin signals. They suppress KNOX internode elongation, activate ABC homeotic genes specifying sepal, petal, stamen, carpel identities, and enforce whorled phyllotaxy with determinate growth. Mutants produce inflorescences where flowers are replaced by shoots bearing leaf-like bracts, demonstrating specific
Ref: Coen & Meyerowitz, Nature 1991; Weigel & Meyerowitz: floral meristem identity genes specify determinate floral meristem.
WOX5 WUSCHEL-related homeobox 5 transcription factor is exclusively expressed in quiescent center cells of root apical meristem functioning analogously to shoot WUS. It moves non-cell-autonomously to surrounding cortex/endodermis and columella initials repressing differentiation-promoting transcription factor CYCLING DOF FACTOR 4 and maintaining stem cell identity. WOX5 sustains PLT gradient, auxin homeostasis, and represses differentiation via local chromatin modifications. Its expression maintained by SHR/SCR and PLT feedback as well as auxin, illustrating conserved WOX-based organizing cent
Ref: Sarkar et al., Nature 2007; Taiz Plant Phys: WOX5 maintains root initial cells and QC organization.
Genetic subtraction seeks to downregulate undesirable endogenous functions rather than introduce novel enzymatic activity. Molecular tools include antisense RNA where transgene produces reverse complement transcript hybridizing to target mRNA, and RNA interference where hairpin construct generates double-stranded RNA processed by Dicer into small interfering RNAs that guide Argonaute mediated cleavage of complementary mRNA. These approaches produce knockdown phenotype resembling loss-of-function mutant, allowing functional genomics and trait improvement. Compared to gene addition that confers
Ref: Watson Molecular Biology Gene 7th ed antisense RNAi; Fire Nature 1998 RNAi; NCBI NBK21471 silencing subtraction; Hannon Nature 2002 mechanism.
Search for effective protease inhibitor for transgenic resistance identified cowpea trypsin inhibitor as potent candidate due to broad activity against lepidopteran gut proteases and stability in alkaline environment. Cowpea Vigna unguiculata seeds accumulate defense proteins to protect against storage pests. Gene CpTI encoding 80 amino acid inhibitor with two disulfide bridges isolated from developing seeds and placed under CaMV 35S promoter. Tobacco transformed with CpTI exhibited 2 to 5 percent soluble protein as inhibitor, reducing tryptic activity of Heliothis virescens midgut extracts an
Ref: Hilder Nature 1987 CpTI cowpea tobacco; Gatehouse Plant Mol Biol 1993 Vigna; NCBI NBK131103; PubMed 3033487 cowpea trypsin inhibitor source.
Cytological analysis visualizes nuclear integrity to uncover ploidy changes and structural rearrangements. Actively growing root tips or callus are pretreated with mitotic inhibitors such as colchicine or paradichlorobenzene to accumulate metaphases, fixed in Carnoy's fluid, hydrolyzed with HCl, and stained with acetocarmine, Feulgen reagent, or fluorescent DAPI binding AT-rich DNA. Squash preparations allow chromosome counting, measurement of arm ratios, and identification of deletions, duplications, translocations, and fragments under light or epifluorescence microscope. Monitoring lagging c
Ref: Sharma & Sharma Chromosome Techniques Butterworth; NCBI NBK21134 karyotyping; PLOS ONE garlic somaclonal cytology 2020; Lodish Ch 20 microscopy.
Modifications of chromosome architecture directly disrupt genetic information storage and segregation. In rapidly dividing callus, spindle aberrations, endoreduplication, telomere attrition, and breakage-fusion-bridge cycles create deletions where segmental DNA is lost, duplications increasing gene dosage, inversions flipping gene order, and reciprocal translocations exchanging arms between non-homologous chromosomes. These events redistribute centromeres, alter linkage maps, expose recessive alleles, and may activate neighboring genes via position effects. Karyotype analysis of long-term cult
Ref: NCBI NBK144424 Chromosome structural aberrations; Lodish Molecular Cell Biology Ch 8; IntechOpen Somaclonal Variation olive; Nature Reviews Genetics translocations.
Somatic hybridization can transfer extensive genetic material ranging from blocks of linked genes to entire chromosomes or whole genomes, contrasting with single gene transformation using plasmid vectors. When two protoplasts fuse, initial heterokaryon contains cytoplasm of both parents and nuclei that may fuse producing allotetraploid somatic hybrid carrying full complement of chromosomes from both species, allowing introgression of polygenic quantitative trait loci QTL controlled by multiple genes interacting for disease resistance, abiotic stress tolerance, quality attributes that cannot be
Ref: Helgeson 1979 potato somatic hybrid; Bhat & Bhat 2011 gene blocks transfer.
Somatic hybridization involves fusion of protoplasts isolated from somatic vegetative tissues of different species cultivars or genera, bypassing sexual incompatibility barriers that prevent conventional crossing due to pre zygotic pollen stigma incongruence or post zygotic endosperm abortion. Protoplasts are obtained by enzymatic digestion of cell walls using cellulase Onozuka R-10 and macerozyme releasing naked cells bounded solely by plasma membrane maintaining totipotency to regenerate wall and divide. Mixed protoplast populations labeled with different fluorescent markers or selectable co
Ref: Gleba & Sytnik 1984 somatic hybridization; Evans et al., Handbook Plant Cell Culture.
Autotetraploids contain four homologous chromosome sets of same species genome, AAAA, derived from doubling of diploid AA genome via colchicine treatment that inhibits spindle formation. Presence of four allele copies increases cell size, nuclear volume, and organ dimensions termed gigas effect due to increased gene dosage and protein production per cell. Leaves become thicker, stomata larger, flowers bigger, fruits heavier, and biomass enhanced, contributing to increased vigor in forage crops like alfalfa and rye grass and ornamental flowers. Photosynthetic rate may rise due to larger chlorop
Ref: Randolph LF. 1932 Autopolyploid vigor; Stebbins GL. Gigas effect. Acquaah Autotetraploid breeding
