monosomics and their cytological identification, recently case studies in related crop species, their breeding behavior also in human being.

1. Content
Introduction
Methods of production
Identification of monosomics
Meiotic behavior of monosomics
Breeding behavior
Use of monosomic analysis
Monosomic in diploid species
Human disorder
Case studies
Monosomics and their effect on crop species

2. Chromosomal
aberration
Structural
chromosom
e aberration
Deletion
Duplication
Interchange
(Translocation)
Inversion
Numerical
chromosom
e aberration
Aneuploid
Hypoploid
Monosomic
(2x-1)
Nullisomic
(2x-2)
Hyperploid
Trisomics
(2x+1)
Tetrasomic
(2x+2)
Euploid
Monoploid
(x)
Haploid (n)
Polyploid
(>2x)
Classification of Chromosomal Aberration
 Haploid (n) :- Half chromosome number of somatic chromosome complement may be diploid
or polyploidy species.
x= Basic chromosome number in true diploid species (2x).

3. Coined by Blakeslee (1921) in Datura stramonium.
Monosomic where one or few chromosomes is missing from the normal diploid
complement or polyploid species.
Represent by (2x-1, 4x-1, 5x-1 etc.).
Maximum number of possible monosomic = Gametic chromosome number
The loss of a chromosome in a diploid species has a more drastic effect on plant
morphology than when it occurs in a polyploid species. Polyploids can tolerate not
diploid (except Maize and tomato - diploid).
Monosomics have been described in great detail by Burnham (1962), Khush (1973),
and Weber (1983, 1991).
During cytological identification different types of monosomics were identified:-
Monotelosomic (20II+1I ) :- Loss of telocentric type chromosome.
Monoisosomic (20II+1I Iso) :- Loss of isochromosome.
Tertiary monosomics (20II+1I translocated ):- Loss of a translocated chromosome.
Double monosomic (19II +1I+1I):- Loss of two different chromosomes.
Ditelosomic (20II+1II telocentric): Fusion of two telocentric chromosome.
Monosomics
Khush, G.S. (1973) in bread wheat

4. Methods of Monosomic Production
1. From haploids:
Accidental production of two haploids in the progeny of cross between
Rye and Chinese spring wheat.
Restitution nucleus
A single nucleus arising from a
failure of nuclear division, either
during meiosis, in which
a gamete is formed with the
unreduced chromosome number; or
at mitosis to give a cell with a
doubled chromosome number.
Sears, E.R. (1939) in Chinese spring
wheat

5. 2. Backcrosses of interspecific hybrids
Clausen and Cameron (1944)
Matsumura (1940)

6. Production of monosomics of A and B genome
Mochizuki 1968 in
tetraploid wheat
3. From partially asynaptic plants

7. 4. Irradiation treatment
Few monosomics in cotton (2n=52)and in oats (2n=42) have been
successfully produced through irradiation of the inflorescence.
Non-disjunction of normal bivalents- production of gametes with n+1
and n-1. 5. Spontaneous production
 Occasional non-disjunction of bivalents during meiosis.

8. Meiotic Non disjunction Generates Aneuploids

9. Cytological
Identification
The center image depicts the FISH
and GISH profiles of the euploid
wild-type hexaploid wheat.
(A) Monosomic 1A
(B) Monosomic 1B
(C) Monosomic 1D
(F) Monosomic 2A
(H) Nullisomic 1A
In FISH, two repetitive DNA
sequences, pSc119.2 (green) and
pAS1 (red), were used as probes.
In GISH, genomic DNAs of
Triticum monococcum (AA) and
Aegilops tauschii (DD) were used
as probes, while genomic DNA of
Aegilops speltoides (BB) was used
as a blocker.
(Zhang et al., 2013)

10. Identification of monosomic in tobacco
When cross between monosomic Nicotiana tabaccum (allotetraploid)
with Nicotiana sylverstris and produced 11II+13I type meant monosomic
in tobacco belonged to sylverstris genome.
Monosomic normal
Nicotiana tabaccum X Nicotiana sylvestris
(2n=35) (2n= 24)
(12II+11I) (12II)
If 11II+13I monosomics
belong to sylvestris genome.
If 12II+11I monosomic
belong to tomentosa genome.

11. Identification of monosomic in cotton
Same as tobacco.
When cross between monosomic Gossipium hirsutum (allotetraploid)
with gossipium ramondii and produced 12II+14I type meant monosomic
in tobacco belonged to ramondii genome.
Monosomic normal
Gossipium hirsutum X Gossipium ramondii
(2n=38) (2n= 26)
(13II+12I) (13II)
If 12II+14I monosomics
belong to ramondii genome.
If 13II+12I monosomic
belong to herbaceum genome.

12. Identification of monosomic in bread wheat
Bread wheat is a allohexaploid species which have three genome A, B
& D genome Triticum monococcum, Ageilops speltoides and Ageilops
squarrosa respectively.
1. Classification of monosomic in durum (A & B genome group and
D genome
2. Distinction between A& B genome
3. Compensation of nullisomic-tetrasomic lines
4. Diplodization system

13. 1. Classification of monosomic in durum (A & B genome
group and D genome
Monosomic normal
Triticum aestivum X T. durum
(2n= 34) (2n= 28)
F1 14II+6I
at meiosis meant due to D genome
or
13II+8I
at meiosis meant due to A/B genome

14. 2. Distinction between A & B genome
Ditelosomic normal
Triticum aestivum X T. monococcum
(20II+1II telocentric) (7II)
F1 7II+13I+1I telocentric
at meiosis meant due to B genome
or
6II+14I+1II hetero bivalent
at meiosis meant due to A genome
Heteromorphic bivalent: A telocentric chromosome fused with
normal chromosome.
Riley and Chapman (1966)

15. 3. Compensating of nullisomic- tetrasomic lines
In wheat, presence of an extra chromosome compensate the phenotypic
effect of the loss of specific chromosome.
Compensating nullisomic-tetrasomic line (19II+1IV) derived from
monosomic wheat (20II+1I) crossed with tetrasomic wheat (20II+1IV).
4. Diplodization system
When polyploid species to behave like diploid at meiosis; due to close
relationship between three genomes.
During monosomic condition (if 5B chromosome absence) formation
of multivalent which show that monosomic for 5B chromosome promote
not only pairing between homologus but also homeologus chromosomes.

16. Monosomics form bivalents and solitary univalents, rarely trivalents.
Univalent shift; formation of more than one univalents due to
failure of association of one/more pairs homologous chromosome,
which gives rise to other monosomics.
Behavior of univalent at meiosis determines the frequency of
gametes with different chromosome constitutions.
Eg: Wheat (2x-1) & tobacco (3x-1) – 75% give monosomic type
Oat (3x-1) – 84-91%
Meiotic behavior

17. • Breeding behavior is
studied by examining the
progeny obtained by
selfing them and crossing
them separately as male
and female parent with
normal's. This helps to
calculate the frequency of
functional deficient
gamete relative to normal.
• Deficient gametes
produced in higher
frequency but function
at low frequency in
pollen.
Breeding behavior of Monosomics

18. Production of monosomic series in a new variety
• Wheat; monosomic series was initially produced in the variety
Chinese Spring.
• For convenient use, one may like to use monosomic series in a
popular variety of his country.
Chinese Spring (monosomic) X popular variety
F1 X popular variety
BC1 X
BC2
BC4-6

19. Uses of Monosomics
• The preparation of linkage map in polyploid species has been
difficult due to the presence of duplicate genes or due to
polysomic inheritance. So a technique known as monosomic
analysis has been successfully used.
• Based on nature of gene, different types of monosomic
analysis are possible.

20. Different types of Monosomic analysis
I. Locating genes for monogenic traits
a. Use of monosomic analysis to locate dominant genes
to chromosomes
b. Use of monosomic analysis to locate recessive genes
to chromosomes
II. Use of monosomic analysis in locating genes to chromosomes for
digenic trait
III. Use of monosomic analysis in locating genes through intervarietal
chromosomal substitutions
IV. Use of monosomic analysis in locating genes on chromosome arms

21. a. Locate dominant genes to chromosomes through F1 analysis
b. Locate dominant genes to chromosomes through F2 analysis

22. 2. Use of monosomic analysis in locating genes to
chromosomes for digenic trait

23. locating genes through inter-varietal chromosomal
substitutions
• If substitution leads to major
change in the morphology for the
character under investigation,
genes for these characters are
present on these chromosome.
• Kuspira and Unrau (1957);
identified genes for lodging,
awning, plant height, earliness,
protein content and 1000 kernel
weight.

24. Locating genes on chromosome arms
Recessive gene Dominant gene

25. • Chromosome 4- Drosophila melanogastor
• X - human being
• Datura stramonium
• Nicotiana alata
• N. longsdorfii
• Solanum lycopersicon
• Zea mays
Monosomics in diploids
Monosomics in diploid obtained by-
• Rare monosomics in the progeny of normal diploid
• Mutation treatment
• Progeny of aneuploids, haploid and polyploids
• Interspecific cross
• Loss due to r-xi deficiency (Maize)

26. Monosomics in human
Monosomy X (Turner Syndrome) is a
karyotypic condition caused by non-
disjunction of X chromosomes at Meiosis
I or II. Frequency is 1 in 5000 female births
Symptoms
1. Short stature
2. Fold of skin
3. Shield shaped thorax
4. Constriction of aorta
5. Poor breast development
6. Elbow deformity
7. Rudimentary ovaries
(sterility)
8. Brown spots
9. Small finger nails
Monosomics for all
human autosomes die
in uterus.

27. I. Morphological characteristics and identification of new
monosomic stocks for cotton (Gossypium hirsutum L.)
Here present morphological features of the cotton (Gossypium hirsutum L.)
monosomic lines developed in Uzbekistan, and their identification.
The current inventory of monosomics lacks deficiencies for five
chromosomes 8, 11, 13, 19 and 24.
Highly inbred line L-458 of G. hirsutum using radioactive irradiation
techniques that resulted in creation of novel sets of monosomic for cotton.
Sanamyan et al. (2010). Advances in Bioscience and Biotechnology, 1: 372-383.
Case study
2. MATERIALS AND METHODS
All aberrant plants were analyzed morphologically. Vegetative and generative
plant organs were studied to reveal new morphological markers.
We studied plant architecture, brunching type, leaf plate, stem and leaf
pubescence, detailed flower morphology including number of stamens and
ovules, as well as structural features of all plant organs.

28. Figure 1. Some examples of morphology of cotton monosomic plants compared to original parental line:
(a) parental line L-458; (b) Mo50; (c) Mo31; (d) Mo76.
a b
c d

35. Result
 We report “reduced” stigma as a new phenotypic marker for cotton
monosomics, which makes it possible to distinguish cytotypes without
cytological analyses.
Some of cotton monosomics lines from these experiment are unique
and should be a valuable cytogenetic tool not only for chromosome
assignment of new marker genes and genome enrichment with new
chromosome deficient plants, but also for a development of new cotton
chromosome substitution lines and germplasm introgression.

36. II. Monosomic analysis of genie male sterility in
hexaploid wheat
• In most of the crops male sterility is controlled by recessive nuclear
gene ms.
• Recently a novel genic male sterility was reported by Singh (2002)
where the male-sterility was incomplete, therefore, it was designated
as p-mst (partial genic male sterility).
• In the present study, an attempt has been made to locate ms gene on
specific chromosome of partial genie male sterile (p-mst) strain.
• Material & methods
• The partial genie male-sterility strain of T.aestivum (2n=42) from the
Department of Genetics, IARI, New Delhi (full awning, single gene
dwarf, late maturing, resistant to stem and leaf rusts of wheat. It
produces 10 to 12% selfed seeds).
• The 21 aneuploid lines of cv. Chinese Spring used were originally
produced by Sears (1954) (awnless and susceptible to rusts).
Research article: Singh, Dalmir and Biswas, P.K. (2002), Wheat Information Service, 95: 1-4

37. Contd..
P-mst F
15: 1
4AF1
425
(Fertile)
151
(partialsterile)
6BF1
280
(Fertile)
101
(Partialsterile)

38. Result
• All the 21 monosomic F1 hybrids produced less number of seeds per
spikelet than disomic F1 hybrid.
• A good fit to a ratio of 15 fertile: 1 sterile was obtained in the F2's of
the disomic cross (control) as well as in the 19 families of the
monosomic F2's.
• In crosses involving chromosomes 4A and 6B expected digenic
segregation was not observed.
Conclusion
• Location of gene for mst trait on chromosome 4A confirms the finding
of Driscoll (1975) and Kleijer and Fossati (1976) where ms genes of
Pugsley and Probus mutants were located on chromosome 4A.
• Location of another gene for mst trait on chromosome 6B is in support
of the findings reported by Sears (1954).

39. Species Ploidy
level
Chr.
No.
No. of
monosomics
obtaibed
Transmission
rate (%)
Seed
fertility (%)
morphology
T aestivum 6x 21 21 62-78 Normal Normal
A sativa 6x 21 21 85-100 Variable Normal
A byzantina 6x 21 12 90-100 28-84 Normal
Tobacco 4x 24 24 5-78 6-10 Modified
American
cotton
4x 26 7+3* 20-40 56-80 Modified
Egyptian
cotton
4x 26 3+1* N.A. N.A. N.A.
Durum 4x 14 14 3-41 9-28 Modified
Maize 2x 10 4 None N.A. Modified
Tomato 2x 12 2+25* None Very poor Highly Modified
Drosophila 2x 4 1 33 - Highly Modified
Datura 2x 12 4 None Very poor Highly Modified
• * Tertiary monosomics N.A. Not ascertained
Monosomics and their effect on crop species

40. 2.

41. 3.

42. 4.
Reference:- Khush, G.S. (1973).Cytogenetics of Aneuploids In: breeding behaviour of
monosomics and nullisomics. Academic Press Inc. (London) LTD.174-194.