Viviana Cambissa a, Loredana Nigro a, Gian Antonio Danieli a & Rodolfo Costa a a Istituto di Biologia Animale, Università di Padova, Via Loredan n.

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1 This article was downloaded by: [ ] On: 22 March 2014, At: 08:06 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: Registered office: Mortimer House, 3741 Mortimer Street, London W1T 3JH, UK Bolletino di zoologia Publication details, including instructions for authors and subscription information: Occurrence of a rare allele at the Est6 locus in natural populations of Drosophila melanogaster Viviana Cambissa a, Loredana Nigro a, Gian Antonio Danieli a & Rodolfo Costa a a Istituto di Biologia Animale, Università di Padova, Via Loredan n. 10, 35100, Padova, Italy Published online: 14 Sep To cite this article: Viviana Cambissa, Loredana Nigro, Gian Antonio Danieli & Rodolfo Costa (1982) Occurrence of a rare allele at the Est6 locus in natural populations of Drosophila melanogaster, Bolletino di zoologia, 49:34, To link to this article: PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the Content ) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sublicensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at

2 Boll. Zool. 49: (1982) Occurrence of a rare allele at the Est6 locus in natural populations of Dsosophiln melaiiogaster v IV I ANA CA hlbi SSA, LOREDANA NIGRO, GIAN ANTONIO DANIEL1 ICODOLFO COSTA Istituto di Biologia Animale, Universiti di Padova, Via Loredan n. 10,35100 Padova (Italy) ABSTRACT An attempt to measure the extent of the variation for nullactivity alleles at the Esterase6 (Est6) locus in Drosophila nrelanogasfer is reported. In the method a laboratory stock was used carrying a third chromosome with an Esf60 allele, balanced with an Est6sultrabithorax (Ubx) chromosome. The results suggest that Est6 null alleles are present at polymorphic frequency in some Italian populations. ACKNOWLEDGEhlENTS We thank hliss P. DAloise and hliss S. De Fianceschi for laboratory assistance. The work was supported by a grant (CT. SO.OOSOS6S.04) from the Consig!io Nazionale del Ie Riccrche (C.N.R.). (Received 1 Jrily 1982) INTRODUCTION The standard surveys of genetic variability by electrophoresis generally provide little information about the frequencies of null alleles in natural populations, since null/active heterozygotes are difficult to distinguish from homozygotes for active alleles. In spite of these difficulties, the presence of nullalleles has been reported so far in several Drosophila species. (0 Brien & MacTntyre, 1978). The presence of a null allele (E~f6~) at the Esterase6 (Est6) locus in D. welatrogasfer was first described in a laboratory strain (Johnson ei al., 1966); however a null activity EsfG allele was found in nature with a frequency of about 0.03 (Trippa el al., 1979). In a recent population survey, devised to trace the presence of null activity alleles in D. melanogasfer, Voelker et ul. (1980) failed to find Esf6 nulls over a sample of 801 chromosomes. This paper reports an attempt to measure the extent of the occurrence for D. tnelarrogaster nullactivity EstG alleles in nature by a procedure using a laboratory stock carrying an E~t6~ balanced chromosome. LIATERIAL AND METHODS The procedure used to detect the presence of null alleles is summarized in Figure 1. The laboratory strain carries a third chromosome with an Esf60 allele in addition to a balanced chromosome with an Esf6S allele and th:: morphological marker Ultrabithorax (Ubx). The Esf60 chromosome originated from a population sample collected at Nauano near Rome (Italy) and analyzed by Trippa ef al. (1979) (see Table 11). Samp!es of Drosophila melanogasfer populations \; ere collected with a fine mesh net over m3sses of squeczed grapes in the open at time of vintage. D. melanogaster wild males were singly mated with virgin females from the laboratory stock carrying the null allele in heterozygosity. From each F, progeny, a random sample of 7 nonubs males was collected and analyzed by vertical gel

3 230 V. CAhlBISSA, L. NICRO, C.A. DANIELI, R. COSTA ~. ~~ COLLECT 7dd FROM EACH PROGENY.FOR ELECTROPHORESIS DISCARD Fig. 1. Scheme of the procedure followed for the identification of null Est60 alleles. polyacrylamide electrophoresis (Danieli el d., 1975) in order to obtain information about the two paternal third chromosomes. RESULTS Two samples of Drosophila melanogarter populations were taken in the region of Venetia (Italy), the first, high in the Euganean Hills at 300 m, about 10 km from Padua, and the second in the plain at Mareno, 60 km away. Both areas are characterized by a relatively mild climate and viticulture. Samples were collected in the early autumn, time of vintage,.when the D. mclatiogaster populations are at maximum size. Seventythree individuals from the Euganean Hills sample and 228 from the Mareno sample were analyzed as described above in Materials and Methods. Results are reported in Table I, together with the HardyWeinberg equilibrium values. The X* has been calculated in order to test obs./exp. ratio on the genotypes. For the Euganean sample X S = S,45; 0,30<p<0,40 while for the Mareno sample X, = 33,71; p<o,ool; thus, the Mareno sample appears not to fit a HardyWeinberg distribution. The distribution of frequencies of Est6 alleles in the two samples is reported in Table 11, and compared with those obtained in previous surveys (Danieli & Costa, 1977; Trippa ct al ); obviously the EstGo dele has been considered in surveys only since 1975 (year of discovery). According to these data, the frequency of the most common allele, EstGs, ranges from 0.66 to 0.78, and that of E~t6~ from 0.16 to 0.25; among the less frequent alleles, the EstGs frequency ranges from

4 ~~ R.~RE ALLELE AT AS ESTERASE LOCUS IS DROSOPIIILA / TABLE I. nistrib1rfio.v of Est6 getlofypes itr lu 0 satnples 01 D.. melaiiogaster poptilafiotis collected in the wi[d rn Venelia (Italy). The expecfed t*alries are ralcrrlated asstinzing fhe existence of 7 Est6 electrophoretic ulleles (S, F, S, F, \IF, VS, 0) and If ardy\veitiberg eqrrilibritrm. _. Euganean Hills hlareno Genotypes sample samplc obs. exp. obs. exp. s/s 45 (44.51) 167 (160.00) FIF 4 ( 1.23) 11 ( 1.21) S/F 11 (15.09) 39 ( 51.91) s/o 6 ( 4.76) 6 ( 6.68) S/VF 1 ( 3.13) 1 ( 0.13) s/vs 1 ( 0.81) ( 1 S/S 2 ( 1.60) 2 ( 2.48) 010 ( 0.12) 1 ( 0.07) S /F ( 0.27) 1 ( 0.40) about to 0.08, that of E~t6~~ from to 0.05, and that of E~t6~ from to about 0.03; E~t6~~ frequency mas found from to about Since most of the differences from placc to place can be ascribed to sampling errors (and this is particularly true for the samples of smaller size) we can assume that in the Mareno and Euganean populations the distribution of frequencies for the Est6 electrophoretic alleles is similar to the general trend previously observed. The frequency of the nu1l EST6O allczymic variant is in the Mareno sample and in the Euganean. Since this variant was found also in the Nazzano population with a frequency of (Trippa et af., 1979), we can reasonably conclude that this allele is present in some Italian populations at polymorphic frequencies, if me adopt a liberal standard in order to consider what constitutes such an allele (p>o.ol). DISCUSSION 23 1 In Drosophiln iirelaizogaster several null alleles of enzyme structural genes were obtained by mutagenic treatment or recovered in natural populations (O Brien & Machtyre, 1978; Voelker et al., 1980; Langley et af., 1981). In spite of the dcnomination of null alleles, most of them are in reality leaky mutants, since a low activity is detectable when suitable analytical procedures are employed. EST6O, described in this paper, can be included in this group since a low activity is detectable after a prolonged gel staining As for the Est6 locus, a significant reduction of viability for the E~t6O/Esl6~ genotype in crosses involving the most common allele E ~t6~ n ~ earlier ~ s observed by Johnson et al. (1966), but recent experiments with Est6 stocks without additional morphological markers suggest that the absence of the EST6 enzymatic activity has little if any effect on viability (Richmond & Claerbout, 1981). Langley et af. (1981) estimated the frequencies for null alleles at 25 allozymcs loci in Drosophiln iirelmogaster and hypothesized that the observed lorn frequencies could be determined, although with significant interlocus heterogeneity, by mutationselection balance. In our case also the observed E ~t6~ frequencies are close to those espected by recurrent mutation, making it hard to analyze a possible action of selection. As to the possible physiological role, high EST6 activity in Drosophifa melaiiogasier was found at the male ejaculatory duct level (Atonstham et af., 1973; Sheehan et d., 1979), and recently it has been suggested that EST6 is involved in the mechanism of reproduction. In fact, Esterase6 enzyme is depleted in males on mating and transferred to females, as a component of the seminal fluid, some minutes before sperm (Richmond et af., 1980). EST6 seems to affect both sperm release

5 232 V. CALIDISSA, L. NIGRO, C.A. DANIEL!, R. COSTA.. TABLE 11. Dislribrrtiotr of alleles ~requerrries in different poprrlafions of D. melanogaster; with exception of the A azzano poprrlation, all satn ples were fafierr in \ rnetia (NorthEast Italy). Sampling Sampling Indivi Gene frequencies sites time duals VS S S F F VF 0 Valdagno Valdagno Aug.Oct Aug.Oct Schio Aug.Oct. U 1971 T CI $ Schio Aug.Oct hlontegrotto 0ct.Jan V1 Saonara 0ct.Nov > $ hlarghcra Aug Casarsa 10 Oct Nauano Oct. (Rome) v) hiareno jept.oct c 2 xs Euganean Oct k Hills 1979 and spermdisplacement and functional differences (Gilbert ef al., 1981) were found at the level of spermstorage and sperrnrelease among EsfGO and Esf6 wild active hornozygous strains. Moreover recent studies on the biochemical properties of EST6 (Costa ef al., 1983) have shown differences between some EST6 allozyrnes concerning also the EST6O (Costa ef a/., 1982). On the basis of these data and on the REFERENCES Aronstham A.A., Kuzin B.A. & Korochkin L.I., 1973 Effect of actinomycin D and cyclohexamidine on the activity of esterase 6 in D. t~~elatrogaster. Isozyme Bull., 6: 24. Costa R., Danieli G.A. 8: Nigro L., 1782 Genetics and biochemistry of Esterase6 in Drosopbila inelanogaster. In Advances in Gcnetics development and evolution of Drosophila, Plenum Publ. Corporation (N.Y.): Costa R., Nigro L., & Danieli G.A., 1983 Est6 allozymes: biochemical studies of two common and one rare variant in DrosoPhila ri~ela phic allelic variant. Danieli G.A. 8: Costa R., 1977 Transient equi

6 ~ RARE ALLELE AT AN ESPERASE LOCUS IN DROSOPHILA 233 librium at the Est6 locus in wild populations of Drosophila melatiogasfer. Genetica, 47: Gilbert D.G., Richmond R.C. & Sheehan R.B., 1981 Studies of Esterase6 in Drosophila ~nelarro~asler V. Progeny production and sperm use in females inseminated by males having active or null alleles. Evolution, 35: Johnson F.hl., \Vallis B.R. & Denniston C., 1966 Reccssive esterase deficiencies controlled by alleles of Est C and Est6 in Drosophila me Imogaster D.I.S., 41: 159. Langley C.H., Voelker R.A., Leigh Brown A.J., Ohnishi S., Dickson B. & hlontgornery E., 1981 Null alleles frequencies at allozyme loci in natural populations of Drosophila melanogasfer. Genetics, 99: O Brien S.J. 8: hlacintyre R.J., 1978 Genetics and biochemistry of enzymes and specific proteins of Drosophila. In The genetics and biology of Drosophila. Vol. 2a. hl. Ashburner and T.R.F. Wright Eds. Academic Press. Richmond R.C. & Claerbout hi.e., 1981 Ratios in crosses segregating for Est60 (Null) and Esterase6s alleles. D.I.S., 56: Richmond R.C., Gilbert D.G., Sheehan K.B., Gromko h1.h. 8: Buttenvorth F.hl., 1980 Esterase6 and reproduction in Drosophila melanogasfer. Science 207: Sheehan K.B., Richmond R.C. & Cochrane B.J., 1979 Studies of Est6 in Drosophila tnelanogaster The developmental pattern and tissue distribution. Insect Biochem. 9: Trippa G., Scozzari R., Costa R. & Danieli G.A., 1979 Polymorphic Estd deficiency in a wild population of Drosophila melanogaster. Egypt. J. Genet., 8: Voelker R.A., Langley C.H., Leigh Brown A.J., Ohnishi S., Dickson B., hlontgornery E. & Smith S.C., 1980 Enzyme null alleles in natural populations of Drosophila melanogasfer: frequencies in a North Carolina p pulation. Proc. Natl. Acad. Sci. USA, 77(2): Printed 17 Jdy 1983