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Susmita Maity ¹, Animesh Kumar Datta ¹

Affiliations
1 Dept. of Botany, Cytogenetics & Plant Breeding Section, Kalyani University, Kalyani-741235, IN

Abstract

Meiotic analysis performed in nine species of jute (cultivated species - C. olitorius L., C. capsularis L.; wild species - C. fascicularis Lamk., C. aestuans L., C. pseudoolitorius I. and Z., C. pseudocapsularis L., C. tridens L., C. trilocularis L. and C. urticaefolius W. and A. - Family: Tiliaceae) revealed that C. olitorius (mean/cell: 7II), C. capsularis (mean/cell: 6.98 II + 0.03 I), C. tridens (mean/cell: 6.98 II + 0.03 I), C. trilocularis (mean/cell: 7 II) and C. urticaefolius (mean/cell: 7 II) formed 2n=14 chromosomes at metaphase I always with balanced (7/7) segregation at anaphase I; while, C. fascicularis Lamk. (24.42%-MI; 1.79%-AI), C. aestuans L. (33.33%-MI; 28.57%-AI), C. pseudoolitorius I. and Z. (24.69%-MI; 15.73%-AI) and C. pseudocapsularis L. (2.56%-MI; 0.00%-AI) exhibited numerical variations in chromosome number (n=1,2,3,4,5,6,9,10 and 14) in addition to normal (n=7). Average chromosome association per cell at MI was 0.002 VI + 0.006 IV + 6.98 II + 0.31I in C. fascicularis, 6.55 II + 0.60 I in C. aestuans, 6.60 II in C. pseudoolitorius and 7.08 II + 0.21 I in C. pseudocapsularis. Aneuploidy noted in jute species is attributed to cytomixis. Chromosome in the species were mostly bivalents (6.55 - 7.08 mean/cell; random in distribution - p> 0.05) and rarely univalents (0.00 - 0.60 mean/cell; nonrandomly distributed - pC. fascicularis. Bivalents in the species were of ring (1.44 ± 0.13 to 4.68 ± 0.14/cell) and rod (2.32 ± 0.14 to 5.44 ± 0.14/cell) configurations. Excepting C. capsularis, the species formed more of rod bivalents than ring. Ring and rod bivalents were nonrandom (p< 0.001); while chiasmata per cell (8.40 - 11.68) and per bivalent (1.20 - 1.67) was random (p> 0.50) in distribution among species as evident from chi - square test of heterogeneneity. Pollen fertility in the species varied from 59.82% - 96.91%.

Keywords

Corchorus Spp., Meiosis, Aneuploid and Polyploid Variations, Cytomixis

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Aninda Mandal ¹, Animesh Kumar Datta ¹

Affiliations
1 Department of Botany, Cytogenetics, Genetics and Plant Breeding Section, Kalyani University Kalyani-741235, West Bengal, IN

Abstract

Three macromutants namely, 'pigmented stem', 'viridis' and 'lax branching', of jute (Corchorus olitorius L. - JRO 524; commercial fibre yielding crop) were induced at M2 following gamma irradiations and EMS (Ethyl Methane Sulphonate) treatments. The true breeding mutants (selfed seeds of a single phenotypically stable plant forwarded in each generation from M4) are assessed considering different attributes like germination, survivability, meiotic chromosome behavior, pollen fertility and viability and quantitative traits across the generations (M5, M6 and M7) in relation to control under a uniform field condition(s). Further, genetic variations between/among the mutants and between mutant(s) and control is also analyzed from seed protein (SDS-PAGE - sodium dodecyl sulphate-polyacrylamide gel electrophoresis), RAPD (Random Amplification of Polymorphic DNA) and ISSR (inter-simple sequence repeat) profiles. Pigment profiles following TLC (Thin Layer Chromatography) have been studied in 'viridis' and control. Inheritance of the mutant trait(s) has also been assessed from reciprocal crossings performed between control and mutants. Results suggest that the mutants are true breeding, stable and significant and may enrich genetic resources in the species.

Keywords

C. Olitorius, Genetic Distinctiveness, Macromutants, Marker Traits, Stability

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Sudha Gupta ¹, Aninda Mandal ¹, Debadrito Das ², Animesh Kumar Datta ²

Affiliations
1 Departments of Botany, Pteridology-Palaeobotany Section, University of Kalyani, Kalyani - 741235, West Bengal, IN
2 Departments of Botany, Cytogenetics, Genetics and Plant Breeding Section, University of Kalyani, Kalyani - 741235, West Bengal, IN

Abstract

Ancient DNA (a-DNA) studies in past three decades has been uplifted from short stretch archaeological mtDNA retrieval to reconstruction of complete mitochondrial genome sequence using next generation sequencing. Study of a-DNA acts as validating tool to test the assumed hypothesis used in origin, evolution, diversification, distribution, domestication and extinction of species; although, scientific progression in the field is frequently hindered by erroneous reports due to contamination and other technical bottlenecks. With the advent of appropriate methodologies such as 3’-C3 spacer tagged oligonucleotide blocking, shotgun sequencing, amplicon sequencing Polymerase Chain Reaction, single primer extension methodology, development of broad spectrum ancient sequence primer, slippage proof amplification methods, use of multiplexing strategy in PCR (Polymerase Chain Reaction) amplification, etc. in a-DNA research try to minimize the difficulties associated with it. Present review highlighted the pitfalls as well as prospects of a-DNA study and tries to assess the significance and acceptability of a-DNA research for its future application in understanding of evolutionary biology.

Keywords

a-DNA, Extraction Difficulties, Modern Technologies, Retrospect of a-DNA

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