HAEMOGLOBIN POLYMORPHISM AND GENETIC IDENTITIES IN FIVE INDIAN COMMENSAL RODENT SPECIES

5 Pages·1991·2.5 MB·

by  M S Pradhan

2
HAEMOGLOBIN POLYMORPHISM AND GENETIC IDENTITIES IN FIVE INDIAN
COMMENSAL RODENT SPECIES1
M. S. PRADIIAN A. M. Biiagwat and S. T. Ingalh4
,
(With two text-figures)
PAGE was used to study haemoglobin polymorphism in five Indian rodent species from
Bombay-Pune region. Rattus rattus rufescens (Gray) showed the maximum number (15) of
bands, whereas Rattus r. wroughtoni Minton had only seven bands. Genetic identities pointed
towards the closeness of Rattus non’egicus (Berkenhout) and BancTtcota hengalensis kok
(Gray). Maximum genetic distance was between R. r. rufescens and R. r. wroughtoni. The
results support the earlier proposal of elevation ofR. r. rufescens to a separate species.
Introduction described by Wright (1974) while the PAGE was
carried out by the method given by Zweig and
Biochemical differentiation of species Whitaker (1967) using 7.5% gels in Tris-HCL
specific proteins could be established by using buffer. Tris-Glycin (pH 8.5) was used as
electrophoretic techniques (Sclander et a/. 1969, electrode buffer. All the bands obtained were
Yoshida et ai 1971, De Smel and William recorded and their mobilities were calculated in
1978). We have already recorded differences in relation to that of the marker Bromophenol blue
electrophoretic mobilities of haemoglobin on (RF values). From such individual records a
paper for Indian commensal rodents from common pattern for the species was evolved.
Bombay-Poona region (Pradhan 1982, Pradhan The genetic identities (I) and genetic distances
el ai 1985); a polymorphic pattern for the (D) were calculated with the help of Nei (1972).
inheritance of haemoglobin in rodents was The dendrogram for the five species was
established. It was, therefore, fell that the use of constructed by unweighted pair-group arithmetic
PAGE to resolve the haemoglobin patterns in average (UPGMA) cluster analysis method
Indian rodents may bring out additional information (Sneath and Sokal 1973). The identification of
regarding haemoglobin polymorphism, frequency each specimen was carried out with the help of
occurrence of polymoiphic locii and possible Ellerman (1961) at Zoological Survey of India,
genetic inter-relations. For the present study five Western Regional Station, Pune, while the
prcdoniinantly commensal species belonging to PAGE was carried out at R. J. College,
two rodent genera, namely Band cota and Rattus Ghatkopar, Bombay.
i ,
were selected.
Results and Discussion
Material and Methods
In the preliminary analysis on PAGE,
About 91 specimens belonging to the five haemoglobin, collected from every specimen of
commensal rodent species were collected from the five selected species, was subjected to
Bombay-Pune region, Maharashtra, with the electrophoretic separation. All the bands
help of municipal workers. The specimens were obtained were recorded and their mobilities
killed for blood sample collection. The were calculated in relation to that of the marker.
haemoglobin was separated as per the methods Bromophenol blue (RF values). From such
common
individual records a pattern for the
1Accepted October 988.
1
species was evolved. Fable records the relative
"Zoological Survey of India, Western Regional Station. 1
Pune- 41KX.I5 mobilities of haemoglobin bands lor the rodent
3 4R. .1. College. Ghatkopar, Bombay-400086. species studied. The same data are represented
230 JOURNAL BOMBAYNATURALHIST. SOCIETY, Vol 88
,
as a consolidated diagrammatic haemoglobin gene locii regulating haemoglobin sysnthesis
profile for individual species (Fig. 1). Of the (Dobzansky et al. 1976, Fitch and Morgoliash
five different v species studied Rattus rattus 1970). On the basis of this assumption a total of
rufescens (Gray) appears to have the maximum as many as 22 bands may be expected for a
haemoglobin polymorphism, with as many as 15 haemoglobin molecule with a single alletic
separate bands, and R. rattus wroughtoni Hinton variation. The pattern of haemoglobin obtained
the minimum, with a total of seven bands. in the present study also is in conformity with
Ferguson (1980) has suggested that the such an assumption.
variations in the mobilities of protein Analysis of consolidated haemoglobin
(haemoglobin) bands may represent a patterns for the five rodent species of two genera
polymorphism at gene locii regulating the Rattus and Bandicoia indicates that several
synthesis of such proteins. Further, the bands have identical electrophoretic mobilities
haemoglobin molecule being a tetramer, in all the species studied. This observation
modification at a single gene locus will give as prompted us to calculate genetic identity (I) and
many as five variants. It is generally accepted genetic distance (D) (Table 2) based on allelic
that among vertebrates, there are at least lour frequencies at each locus (Nci 1972). Based on
Table
1
HAEMOGLOBIN VARIANTS IN TERMS OF VALUES, THEIR OCCURRENCE AND FREQUENCIES IN THE
POPULATIONS OF FIVE COMMENSALRODENTSPECIES
Names ofspecies RF values with S.D. No. of % population % frequency
hands (occurrence) of bands
—
n=Total No. ofspecimens 0.1 ± 2 6.1 2.6
0.18 ±0—.02 3 9.1 3.8
>>
nb=fital »o. of bands 0.23 ± — 1 3.0 1.3
JGIDI 0.3 ± — 2 6.1 2.6
£ >* 0.34 ± — 1 3.0 1.5
OUrn 0.38 ± 3 9.1 3.8
5 0.42 ± 0.01 4 12.1 5.1
m
c*i 0.46 ± 0.02 14 42.4 17.9
rO
GII 0.5 ± 0.01 8 24.2 10.3
0.52 ±0.01 4 12.1 5.1
0.55 ± 0.01 10 30.3 12.8
0.58 ±0.01 9 27.3 11.5
0.67 ± 0.01 13 39.4 16.6
0.7 ± 0—.01 3 9.1 3.8
>5 0.89 ± 1 3.0 1.3
G
ii
•**- _D
y0/5 l c 0.21 ± 0.01 2 13.3 4.4
C
k. V 0.25 ± 0.07 2 13.3 4.4
CN
JZ
ow. 0.30 ± 0.01 4 26.6 8.7
>5
•*4 2Q 0.34 ± 0.01 2 13.3 4.4
•
<5
cII 0.38 ± 0.01 3 19.9 6.5
0.45 ± 0.01 9 59.9 19.6
0.49 ± 0.01 8 53.3 17.4
0.53 ± 0.01 6 39.9 13.1
0.59 ± —0.02 8 53.3 17.4
0.65 ± 2 13.3 4.4
u
5H
HAEMOGLOBINPOLYMORPHISM INRODENTSPECIES 231
Table 1 (contd.)
Names ofspecies RF values with S.D. No. of % population % frequency
bands (occurrence) of bands
CNm 0.4 ± 1 9.1 4.6
5 '<N 0.45 ± 1 9.1 4.6
II
3 -cO 0.5 ± 0.01 3 27.3 13.6
5
00 0.53 ± 0.01 5 45.5 22.7
3S
S 0.59 ± 0.01 6 54.6 27.2
S
oi 0.63 ±0 .01 3 27.3 13.6
II
0.66 ± 0.01 3 27.3 13.6
—
0.31 ± 7.7 3.6
1
53 oq 0.36 ± 0.02 4 30.8 14.3
5J fsj
8 II 0.42 ± 0.01 4 30.8 14.3
•<V3. •5 -c§ J8= a 0.46 ± 0.01 5 38.5 17.9
8 .53 ^CQ 0.49 ± 0.01 5 38.5 17.9
**• 53 ri—o 0.53 ± 0.01 3 23.1 10.7
C533 cII 0.57 ± 0.01 3 23.1 10.7
0.62 ± 0.02 3 23.1 10.7
—
0.32 ± 1 5.3
't 0.39 ± 0.0.1 5 26.3 10
s <**= t SII 0.45 ± 0.01 8 42.1 16
c.
8 'j 0 >; 0.49 ± 0.01 7 36.8 14
«5
"S3 5o3o wO 0.53 ± 0.01 1 57.9 22
a
<3 f “,50< r-^ 0.59 ± 0.01 7 36.8 14
cII 0.65 ± —0.01 4 21.4 8
0.71 ± 1 5.3
Fig. 1. Consolidated diagrammatic haemoglobin profile for individual species
R.r.w. = Rattus rattus wroughtoni. R.r.r. = R. r. rufesccns, R.n. = R. norvegicus, B.b.k. = Bandicola bengalensis kok (lordi),
B.i.i. = B. indica indica (malaharica) , n = no. ofspecimens. Numbers near the bands show number of occurrences of each
band in the population.
)
JOURNAL JSOMBAYMATURAUI/ST. SOCIF1Y. XX
Vol.
Genetic Identity (I
0. 0-1 0-2 0-3 0-4 0 5 0-6 0-17 10-8 0-9 1-0
I 1 1 L I I I I I
Rattus norvegicus
Bandicota bengalensis
w
Rattus roughtoni
r.
Bandicota indica indica
Rattus rutescens
r.
Fig. 2. Dendrogram showing relationships between species ge crated by cluster analysis
these values of I, the unweighted pair-group Rattus norvegicus has a striking similarity, not
method with arithmetic means (UPGMA) of only in morphology but also in habit and
Sneath and Sokal 1973, was applied to construct habitats,- to the indigenous B. bengalensis.
a dendrogram for these five species (Fig. 2). In Extensive mixing of these two genera has been
terms of genetic identity for haemoglobin locii, reported in urban areas like Bombay, Calcutta,
all the species studied arc rather closely related Madras, etc. Under these conditions a possibility
(1=0.69 to 0.91). However, amongst these, that these rodents could be interbreeding cannot
Bandicota benga/crisis and Rattus norvegicus be ruled out. Such a possibility has already been
arc the closest (1=0.91) followed by R. rattus expressed in rodents possessing white patch
wroughtoni (1=0.8), B. indica (0.71) and Rattus (Pradhan and Mithel 1981).
rattus rufescens (1=0.69). House rat Rattus Comparison of Rattus rattus rufescens and
rattus rufescens is closer to Bandicota indica R. /: wroughtoni indicates that these two
than any other species (1=0.77). subspecies of the species Rattus rattus have the
The genetic identities of Bandicota maximum genetic distance (D=0.48, 1=0.62) for
bengalensis and Rattus norvegicus raise certain the haemoglobin locii. These results when ‘aken
doubts and speculations. The exotic species together with karyotypic differences reported by
Fab 2
li
ESTIMATION OF GENETIC IDENTITY (BELOW DIAGONAL) AND GENETIC DISTAN< T.S (ABOVE DIAGONAL)
AMONG MEMBERS OF FIVE SPECIES OF ’IWO COMMENSALRODENTS BASED ON NEL 1972
Serial Names of the species 1 2 3 4 5
No.
—
1 . Rattus rattus rufescens (Gray) 0.—48 0.27 0.30 0.26
2. Rattus rattus wroughtoni Minton 0.62 0.—32 0.17 0.48
3. Rattus norvegicus (Berkenhout) 0.76 0.75 0—.2 0.29
4. Bandicota bengalensis kok (lordi) (Gray) 0.74 0.84 0.91 0.—29
5. Bandicota indica indica (malaharica) (Beck.) 0.77 0.62 0.82 0.75
HAEMOGLOBINPOLYMORPHISMINRODENTSPECIES 233
Sharina and Raman (1971) in these two AcKN()\VLHIXJIiMl-NTS
subspecies, are in support of the earlier Our sincere thanks are due to the Director,
suggestion to elevate R. rattus rufescens to a Zoological Survey of India, Calcutta, the
separate species (Tiwari et ol. 1972). Therefore Officer-in-charge, Z.S.I., W.R.S., Pune, and the
we feel that, under the present circumstances, a Principal, R. J. College, Ghatkopar, Bombay, for
detailed study should be undertaken to confirm providing the laboratory and other facilities. We
the present taxonomic status of R. rattus also thank the Municipal Corporations of
rufescens. Greater Bombay and Pune for help in the rodent
collection.
R EFEk NCES
If.
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