monosomics and their role in cytogenetics

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 monosomicanalysis
Monosomicin diploid species
Human disorder
Case studies
Monosomicsand 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 Daturastramonium.
Monosomicwhere one or few chromosomes is missing from the normal diploid
complement or polyploidspecies.
Represent by (2x-1, 4x-1, 5x-1 etc.).
Maximum number of possible monosomic= Gameticchromosome number
The loss of a chromosome in a diploid species has a more drastic effect on plant
morphology than when it occurs in a polyploidspecies. Polyploidscan tolerate not
diploid (except Maize and tomato -diploid).
Monosomicshave been described in great detail by Burnham (1962), Khush(1973),
and Weber (1983, 1991).
During cytological identification different types of monosomicswere identified:-
Monotelosomic(20
II
+1
I
) :-Loss of telocentrictype chromosome.
Monoisosomic(20
II
+1
I
Iso):-Loss of isochromosome.
Tertiary monosomics(20
II
+1
I
translocated):-Loss of a translocatedchromosome.
Double monosomic(19
II
+1
I
+1
I
):-Loss of two different chromosomes.
Ditelosomic(20
II
+1
II
telocentric): Fusion of two telocentricchromosome.
Monosomics
Khush, G.S. (1973) in bread wheat

4. Methods of MonosomicProduction
1.Fromhaploids:
Accidental production of two haploids in the progeny of cross between
Rye and Chinese spring wheat.
Restitutionnucleus
Asinglenucleusarisingfroma
failureofnucleardivision,either
duringmeiosis,inwhich
agameteisformedwiththe
unreducedchromosomenumber;or
atmitosistogiveacellwitha
doubledchromosomenumber.
Sears, E.R. (1939) in Chinese spring
wheat

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

6. Production of monosomicsof A and B genome
Mochizuki1968 in
tetraploidwheat
3. From partially asynapticplants

7. 4. Irradiation treatment
Few monosomicsin 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 duringmeiosis.

8. Meiotic Non disjunction GeneratesAneuploids

9. Cytological
Identification
ThecenterimagedepictstheFISH
andGISHprofilesoftheeuploid
wild-typehexaploidwheat.
(A)Monosomic1A
(B)Monosomic1B
(C)Monosomic1D
(F)Monosomic2A
(H)Nullisomic1A
InFISH,tworepetitiveDNA
sequences,pSc119.2(green)and
pAS1(red),wereusedasprobes.
InGISH,genomicDNAsof
Triticummonococcum(AA)and
Aegilopstauschii(DD)wereused
asprobes,whilegenomicDNAof
Aegilopsspeltoides(BB)wasused
asablocker.
(Zhang et al., 2013)

10. Identification of monosomicin tobacco
When cross between monosomicNicotianatabaccum(allotetraploid)
with Nicotianasylverstrisand produced 11
II
+13
I
type meant monosomic
in tobacco belonged to sylverstrisgenome.
Monosomic normal
NicotianatabaccumX Nicotianasylvestris
(2n=35) (2n= 24)
(12
II
+11
I
) (12
II
)
If 11
II
+13
I
monosomics
belong to sylvestrisgenome.
If 12
II
+11
I
monosomic
belong to tomentosagenome.

11. Identification of monosomicin cotton
Same as tobacco.
When cross between monosomicGossipiumhirsutum(allotetraploid)
with gossipiumramondiiand produced 12
II
+14
I
type meant monosomic
in tobacco belonged to ramondiigenome.
Monosomic normal
GossipiumhirsutumXGossipiumramondii
(2n=38) (2n= 26)
(13
II
+12
I
) (13
II
)
If 12
II
+14
I
monosomics
belong to ramondiigenome.
If 13
II
+12
I
monosomic
belong to herbaceumgenome.

12. Identification of monosomicin bread wheat
Bread wheat is a allohexaploidspecies which have three genome A, B
& D genome Triticummonococcum, Ageilopsspeltoidesand Ageilops
squarrosarespectively.
1.Classification of monosomicin durum (A & B genome group and
D genome
2.Distinction between A& B genome
3.Compensation of nullisomic-tetrasomiclines
4.Diplodizationsystem

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

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

15. 3. Compensating of nullisomic-tetrasomiclines
In wheat, presence of an extra chromosome compensate the phenotypic
effect of the loss of specific chromosome.
Compensating nullisomic-tetrasomicline (19
II
+1
IV
)derived from
monosomicwheat (20
II
+1
I
) crossed with tetrasomicwheat (20
II
+1
IV
).
4. Diplodizationsystem
When polyploidspecies to behave like diploid at meiosis; due to close
relationship between three genomes.
During monosomiccondition (if 5B chromosome absence) formation
of multivalent which show that monosomicfor 5B chromosome promote
not only pairing between homologusbut also homeologuschromosomes.

16. Monosomicsform bivalents and solitary univalents, rarely trivalents.
Univalent shift; formation of more than one univalentsdue 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 monosomictype
Oat (3x-1) –84-91%
Meiotic behavior

17. •Breedingbehavioris
studiedbyexaminingthe
progenyobtainedby
selfingthemandcrossing
themseparatelyasmale
andfemaleparentwith
normal's.Thishelpsto
calculatethefrequencyof
functional deficient
gameterelativetonormal.
•Deficientgametes
producedinhigher
frequencybutfunction
atlowfrequencyin
pollen.
Breeding behavior of Monosomics

18. Production of monosomicseries in a newvariety
•Wheat; monosomic series was initially produced in the variety
ChineseSpring.
•For convenient use, one may like to use monosomic series ina
popular variety of hiscountry.
Chinese Spring (monosomic) X popularvariety
F
1 X popular variety
BC
1X
BC
2
BC
4-6

19. Uses ofMonosomics
•The preparation of linkage map in polyploid species has been
difficult due to the presence of duplicate genes or due to
polysomicinheritance. So a technique known as monosomic
analysis has been successfullyused.
•Based on nature of gene, different types ofmonosomic
analysis arepossible.

20. Different types of Monosomicanalysis
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 chromosomesfor
digenictrait
III. Use of monosomic analysis in locating genes through intervarietal
chromosomal substitutions
IV. Use of monosomic analysis in locating genes on chromosomearms

21. a. Locate dominant genes to chromosomes through F
1 analysis
b. Locate dominant genes to chromosomes through F
2 analysis

22. 2. Use of monosomicanalysisin locating genesto
chromosomes for digenictrait

23. locating genes through inter-varietalchromosomal
substitutions
•Ifsubstitutionleads to major
change in the morphology for the
character under investigation,
genes for these characters are
present on thesechromosome.
•Kuspiraand Unrau(1957);
identified genes for lodging,
awning, plant height,earliness,
protein content and 1000kernel
weight.

24. Locating genes on chromosomearms
Recessive gene Dominant gene

25. •Chromosome 4-Drosophilamelanogastor
•X-humanbeing
•Daturastramonium
•Nicotianaalata
•N.longsdorfii
•Solanumlycopersicon
•Zeamays
Monosomicsindiploids
Monosomicsin diploid obtainedby-
•Rare monosomics in the progeny of normaldiploid
•Mutationtreatment
•Progeny of aneuploids, haploid andpolyploids
•Interspecificcross
•Loss due to r-x
ideficiency (Maize)

26. Monosomicsinhuman
Monosomy X (Turner Syndrome) is a
karyotypic condition caused by non-
disjunction of X chromosomes atMeiosis
I or II. Frequency is 1 in 5000 femalebirths
Symptoms
1.Shortstature
2.Fold ofskin
3.Shield shaped thorax
4.Constriction of aorta
5.Poor breast development
6.Elbow deformity
7.Rudimentary ovaries
(sterility)
8.Brownspots
9.Small fingernails
Monosomics for all
human autosomes die
inuterus.

27. I. Morphological characteristics and identification of new
monosomicstocks for cotton (GossypiumhirsutumL.)
Herepresentmorphologicalfeaturesofthecotton(GossypiumhirsutumL.)
monosomiclinesdevelopedinUzbekistan,andtheiridentification.
The current inventory of monosomicslacks deficiencies for five
chromosomes 8, 11, 13, 19 and 24.
Highly inbred line L-458 of G. hirsutumusing radioactive irradiation
techniques that resulted in creation of novel sets of monosomicfor cotton.
Sanamyanet 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 monosomicplants 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 cytotypeswithout
cytological analyses.
Some of cotton monosomicslines 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 germplasmintrogression.

36. II. Monosomicanalysis of genie male sterilityin
hexaploidwheat
•In most of the crops male sterility is controlled by recessive nuclear
genems.
•Recently a novel genicmalesterility was reported by Singh (2002)
where the male-sterility was incomplete, therefore, it was designated
as p-mst(partial genicmalesterility).
•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% selfedseeds).
•The 21 aneuploid lines of cv. Chinese Spring used wereoriginally
produced by Sears (1954) (awnless and susceptible torusts).
Researcharticle: Singh, DalmirandBiswas, P.K.(2002),WheatInformationService,95:1-4

37. Contd..
P-mstF
15:1
4AF
1
425
(Fertile)
151
(partialsterile)
6BF
1
280
(Fertile)
101
(Partialsterile)

38. Result
•All the 21 monosomic F
1 hybrids produced less number of seeds per
spikelet than disomic F
1hybrid.
•A good fit to a ratio of 15 fertile: 1 sterile was obtained in the F
2's of
the disomic cross (control) as well as in the19 families of the
monosomic F
2's.
•In crosses involving chromosomes 4A and 6B expected digenic
segregation was notobserved.
Conclusion
•Location of gene for msttrait on chromosome 4A confirmsthe finding
of Driscoll (1975) and Kleijerand Fossati(1976) where ms genes of
Pugsleyand Probusmutants were located on chromosome4A.
•Location of another gene for msttrait 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
Taestivum6x 21 21 62-78 Normal Normal
A sativa6x 21 21 85-100 VariableNormal
A byzantina6x 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 poorHighly Modified
Drosophila2x 4 1 33 - Highly Modified
Datura 2x 12 4 None Very poorHighly Modified
•* Tertiary monosomics N.A. Not ascertained
Monosomicsand their effect on crop species

40. 2.

41. 3.

42. 4.
Reference:-Khush, G.S. (1973).Cytogeneticsof AneuploidsIn:breeding behaviourof
monosomicsand nullisomics. Academic Press Inc. (London) LTD.174-194.