103(4)-01(27).fm

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1 J. Korean For. Soc. Vol. 103, No. 4, pp. 519~527 (2014) JOURNAL OF KOREAN FOREST SOCIETY ISSN (Print), ISSN (Online) 고유종꼬리말발도리의생식특성과동위효소유전다양성 장진성 1 김휘 2 * 1 서울대학교산림과학부 ( 부속수목원 ), 2 목포대학교한약자원학과 ( 한방산업연구소 ) Breeding System and Allozyme Genetic Diversity of Deutzia paniculata Nakai, an Endemic Shrub in Korea Chin-Sung Chang 1 and Hui Kim 2 * 1 Department of Forest Sciences and The Arboretum, Seoul National University, Seoul , Korea 2 Department of Medicinal Plants Resources, Mokpo National University and Institute of Oriental Medicine, Muan-gun , Korea 요약 : 고유식물인꼬리말발도리는팔공산, 달음산, 가지산과운문산등경상남북도에제한적으로분포한다. 본연구대상인 4개집단의크기는달음산의최소 100개체에서운문산집단이최대 3,500개체까지이다. 인공수분실험결과, 생식양식은완전타가수분이며, 주요관찰화분매개자는 Lasioglossum exiliceps (Vachal) 과호리꽃등에 [Allograpta balteata (de Geer)] 였다. 동위효소로유전적다양성을측정한결과, 종수준에서의평균적인유전다양성은유전자좌당평균대립유전자수 (A s ) 는 1.33, 유전다양성 (H es ) 은 0.110으로이미보고된고유식물종의유전다양성과비슷한값을보였다. 달음산집단은모든개체에서동일한유전적조성을보였으며, 이집단의전체개체가클론으로추정된다. 유전자좌의비율 (P) 과유전자좌당평균대립유전자 (A P ) 의수는팔공산집단이가장높았다. 집단간의전체유전고정지수 (F IT ) 는집단내지수 (F IS ) 보다높아집단내이형접합자의비율은높지만, 종전체이형접합자부족현상이확인되었다. 집단간의유전적분화의정도를나타내는 F ST 값은 0.223, 각집단간의유전적거리는평균 0.047( ) 로단형성을갖는유전자가많아실제분화는일부유전자좌에국한된결과이다. 꼬리말발도리의유전다양성의감소는집단의유효집단크기감소와관련이있으며, 현지내의생육지보전과함께현지외보전을위해각집단별로최대유전다양성을확보하는전략이필요하다. Abstract: Deutzia paniculata is an endemic species, which is geographically restricted within southern part of Korea. Four populations of D. paniculata were sampled across its natural range, from the smallest population, Mt. Dalum, which held less than 100 individuals, to the largest, Mt. Unmum, over 3,500 individuals. Artificial pollination study showed that D. paniculata had an obligate outcross breeding system. Major pollinators were two bee species, Lasioglossum exiliceps and Allograpta balteata (de Geer). The breeding system and patterns of allozyme variation of D. paniculata were investigated to understand the population biology and to explain on reserve designs and management proposals relevant to this species. D. paniculata held relatively low genetic variation at the eight allozyme loci surveyed. Measures of genetic variation in this species alleles per locus (A s =1.33), proportion of polymorphic loci (P=23.85%), and expected heterozygosity (H es =0.110) were similar to values reported for endemic species. Mt. Dalum population (DAL) was composed with one clone based on allozyme data. Individuals of D. paniculata were frequently included in root connected clusters. Population genetic structure between and within four populations was probably the result of shrinking effective population size and the extinctions of intervening populations. For the conservation of genetic diversity, maximum number of different genotype need to be protected based on genetic structure and mating system. Key words: allozyme, breeding system, Deutzia paniculata, endemic, genetic diversity 서 론 한국고유종인꼬리말발도리 (Deutzia paniculata Nakai) 는매화말발도리절 (sect. Deutzia C.K. Schneid.), 애기말발 *Corresponding author huikim@mokpo.ac.kr 도리열 (ser. Gragilis) 로 (Zaikonnikova, 1966), 근연종인일본의 D. gracilis Siebold & Zucc. 에비해반이하로작으며, 잎의모양이난형으로장타원형인 D. gracilis와구별된다. 북한원산이최초기재된채집지이고, 현재는경상남도동부산지와대구팔공산과경상북도남부일부산지에분포한다 (Chung and Shin, 1986). 꼬리말발도리의제 519

2 520 韓國林學會誌제 103 권제 4 호 (2014) 한된분포특성을고려할경우, Rabinowitz et al.(1986) 이구분한희귀식물의일곱가지유형중지리적으로좁게분포하면서특정생육지에서국지적으로좁은면적을점유하는유형이다. Chang et al.(2001) 은 IUCN 적색목록의범주 (category) 와평가기준 (criteria) 에의해꼬리말발도리를멸종을제외한멸종위협이되는범주중위급 (CR, Critically Endangered) 으로판정하여보전의위급성을밝혔다. 최근외국에서의보전활동의경우, 종에대한정보수집의범위는분류학적판단이외에도, 분포와관련된정보, 생활형, 고도분포, 생육지의다양성및경제적이용등다양하다 (Young, 2007). 국내에서다양한고유식물종에대한유전변이연구가있었으나, 이를보전에적극적으로활용하지는못하고있다 (Chung et al., 2010; Park et al., 2010). 최근희귀멸종위기식물의복원에대한연구는이러한유전정보에기초하지않고클론 (clone) 번식으로단순증식만에의존하고있다 (Bae et al., 2012). 특히, 산림청은고유식물을관리하기위한관련종을법률로지정하는작업을실시하였는데 (Park et al., 2013), 고유종의보전을위해서는국가단위의국경선을중심으로한특정지역의고유성목록을단순제시하기보다는종의위협상황에대한모니터링과희귀성에대한유형분석, 멸종위기와관련된환경적인자에대한역동적인실태가필요하다 (Park et al., 2013; Kruckerberg and Rabinowitz, 1985). 구체적인모니터링의목표는해당종에대한명확한종풍부도의증감에대한자료를제시함과함께종의분포및위협원인에대한평가를해야한다 (Pauli et al., 2012). 멸종위기종의야생집단에대한유전구조연구는집단간 / 집단내유전변이를이해할수있을뿐만아니라집단내, 집단간변이의분포, 그리고집단내유효집단의크기 (effective population size) 와집단간의유전자이동에대한정보를얻을수있다 (Given, 1994). 집단유전분석을통한표본추출의체계화는잘계획된희귀식물의복원방법으로서성공가능성이매우높다 (Barrett and Kohn, 1991). 특히, 단순한개체확보보다는유전다양성에근간을둔집단복원방법은장기적으로종보전의성공가능성이높다 (Aavik et al., 2012). 본연구는현지내보전 (in situ conservation) 계획수립및체계화된현지외 (ex situ) 보전을위해유전다양성을조사하여집단의유전구조에대한자료를확보하고이를근간으로자생지에서의보전방안을제시하고자한다. system) 과화분매개곤충 (pollinator) 을확인하기위하여운문산지역과팔공산지역에서매개곤충을포획동정을하였다. 화기가가장정점에이른시기에오전부터오후까지일정한면적의꼬리말발도리집단에 8시간이상꼬리말발도리의꽃을찾아수분행동을보이는곤충을채집하였다. 방화곤충중단순방화행동을보이는종과구별하기위하여꼬리말발도리의화분을모으는종을주요화분매개충으로결정하였다. 꼬리말발도리의교배양식 (breeding system) 연구를위하여, 운문산지역에서개화된개체들을대상으로수분실험을실시하였다. 교배양식은 4가지처리 (outcrossing, selfing, geitonogamy, bagging) 를 10반복으로실시하였다. 각각의교배처리를위하여이미완전개화한꽃은제거하였고, 개체당아래 4가지교배처리를한후색깔이서로다른라벨로표기하였다. 완전자가수분 (selfing) 의경우동일한꽃의수술로부터얻은꽃가루를암술에수분을실시하였고, 개체내다른꽃으로부터수분 (geitonogamy) 은동일한개체의다른꽃으로부터얻은꽃가루를암술에수분을실시하였고, 완전타가수분 (outcrossing) 은수술제거후집단내 100 m 이상떨어진개체로부터얻은꽃가룰암술에수분을실시하였다. 또한 재료및방법 1. 생식특성집단내유전구조에영향을주는교배양식 (breeding Figure 1. Four populations ( ) of D. paniculata in south Korea for allozyme analysis. Several known locations ( ) based on Nakai (1921) and Chung and Shin (1986) are presented here.

3 고유종꼬리말발도리의생식특성과동위효소유전다양성 521 Table 1. Sample localities of D. paniculata. Population names are accompanied by acronyms that are used to refer to the populations elsewhere. Populations with acronyms Localities Unmunsan (UNM), Milyangsi, Gyongsangnam-do N35 36'44.7" E128 57'43.2" Dalumsan (DAL), Gijanggun, Busan N35 14'34.1" E129 11'49.5" Palgongsan (PAL), Daegu N36 01'05.6" E128 41'07.7" Gajisan (GAJ), Unyangeup, Ulsan N35 38'27.5" E129 02'36.2", 수분매개자배제 (bagging) 는같은수의반복을실시하였으며, 대조구 (control) 의경우화서만을같은반복수로표기하였다. 2. 유전다양성집단유전분석을위해경상남도밀양시운문산 (UNM), 부산광역시기장군달음산 (DAL), 대구광역시팔공산 (PAL), 울산광역시울주군언양읍가지산 (GAJ) 등 4개지역에서시료를채취하였다 (Figure 1, Table 1). 현지내에서의시료채취는집단내에서개체간최소 20 m 간격으로최대 50 개체에서최소 45 개체씩시료를채취하였으나, 달음산 (DAL) 집단의경우만예외로발견된 100여개체에서 50 여개체를채취하였다. 채집된시료는 Phosphate buffer (50 mm), Mercaptoethanol(14 mm), PVP-40(5%), 그리고 Bovine serum albumin(0.1%) 를이용하여효소를추출하여 Whatman chromatography paper에흡수시킨후전기영동실험을하기전까지 -70 o C에보관하였다. 전기영동은 12% 의전분젤을이용하여모두다섯가지조합의 Gel/electrode buffer를이용하였다. 조사한효소는 catalase(cat), glutamine dehydrogenase(gdh), glutamate oxalacetate transaminae(got), glucouse 6-phosphate dehydrogenase(g6pdh), leucine amino peptidase(lap), malate dehydrogenase(mdh), malic enzyme(me), phosphoglucoisomerase(pgi), phosphoglucomutase(pgm), peroxidase(per), isocitrate dehydrogenase(idh), 6-phophogluconic acid dehydrogenase(6gpd), shikimic acid dehydrogenase(skd), menadione reductase(mnr) 등모두 14개의동위효소를분석하여 22개의유전자좌를확인할수있었다. Gel/ electrode buffer의조합은다음과같다 (Conkle, 1982); A -Lithium-borate, B-Sodium-borate, C-Tris-citrate, D- Morpholine-citrate, H-Histidine-citrate. 동위효소의염색방법은 Conkle et al.(1982) 의방법을이용하였고, 밴드에서나타나는추정상의유전자좌 (locus) 는가장양극쪽으로이동한것부터 1번, 2번등으로정하였다. 추정상의유전자좌의대립유전자도또한가장양극에가까운것부터 a, b, c 등으로표시하였다. 모든효소의구조와밴드의유전적해석은 Kephart(1990) 의방법을따랐다. 종수준및집단수준의유전다양성을나타내는다형 성 (polymorphism) 을보이는유전자좌의비율 (percentage of polymorphic loci; P) 과유전자좌당유효유전자의수 (effective number of alleles per locus; Ae), 유전자좌당평균대립유전자의수 (mean number of alleles per locus; A) 를측정하였으며, 집단간의변이 (interspecific variation) 를측정하는데는 2가지방법이이용하는데, 대립유전자빈도에근거한표준변이에대한집단들간의대립유전자빈도를계산하는 Wright(1951) 의 F-statistic을계산하였다. 그리고기대이형접합률 (He) 를구하고, F-statistics, χ 2 -test 를통해 Hardy-Weinberg 법칙에따르는지를집단별로조사하며, genetic identity(i distance, Nei, 1973, 1978) 등을계산하였다. 유전자이동자수 (Gene flow) 는 Wright의공식 (Wright, 1951) 을이용하여유전자이동자수 (Nm) 를구하였으며, Wright의공식 (Wright, 1951) 을변형시킨 Crow and Aoki (1984) 의공식 Fst =1/(4Nma+1) 을이용한유전자이동자수 (gene flow) 도계산하였다 (α=[n/(n-1)] 2, n은집단의수 ). 유전자형빈도 (genotypic frequency) 는 Hardy-Weinberg 법칙에따라기대이형접합도와어떤차이를보이는지확인하였다. 모든자료의분석은 BIOSIS-1 program(swofford, 1989) 을이용하여분석하였다. 또한, Crow and Kimura (1970) 의공식을이용현재의기대이형접합률 (He) 을유지하기위한유효집단의크기 (effective population size; Ne =He/[4µ(1-He)]) 를제시하였다. 결과 1. 생식특성꼬리말발도리의화분매개충을파악하기위하여운문산과팔공산지역에서장기간관찰한결과주요화분매개자는벌목 (Hymenoptera) 의꿀벌과 (Apidae) 의 Lasioglossum exiliceps (Vachal) 이었으며파리목 (Diptera) 의꽃등에과 (Syrphidae) 호리꽃등에 [Allograpta balteata (de Geer)] 등이가장중요한화분매개충으로확인되었다. 후자의경우적극적인화분수집은미약하고벌종류와는달리화분을몸에따로저장하는기능이미약하여 2차적중요방화곤충으로확인되었다. 꼬리말발도리의교배양식을파악하기위하여운문산지역의개체들을대상으로수분실험을

4 522 韓國林學會誌제 103 권제 4 호 (2014) Figure 2. Pollination type and percentage fruit set in wild population of D. paniculata. 실시한결과각처리 (outcrossing, selfing, geitonogamy, bagging) 중 3가지처리인완전자가수분 (selfing), 개체내다른꽃으로부터수분 (geitonogamy), 수분매개자배재 (bagging) 에서는전혀결실된종자를얻을수없었다. 완전타가수분 (outcrossing) 을전체 10개의반복에서평균 3 개교배가성공된것을확인하였다 (Figure 2). 완전타가수분과대조구에서만교배가성공한것으로확인되어꼬리말발도리의교배양식은자가수분이배제되는타가수분이주요교배양식임을확인하였다. 2. 유전다양성 22개의유전자좌중 8개의유전자좌 (GOT-2, PGI-2, GDH-1, MNR-1, PER-1, PER-2, PGM-2, 6PGD-2) 에서종수준의다형성 (polymorphism) 을확인하였다. 다형성을보이는유전자좌의대립유전자의수는최대 3개였으며, 유전자좌당평균대립유전자수 (A s ) 는 1.33, 유전다양성 (H es ) 은 0.110이었다 (Table 2). 부산기장군의달음산집단 (DAL) 은모든개체에서 8개의다형성동위효소유전형으로는동일유전형으로보여단일클론일가능성이높다 (Table 3). 유전좌를이용다형성을나타내는유전자좌의비율 (P) 은전혀유전다양성을보여주고있지않은달음 산집단 ( 종수준에서가장높은다형성을보이는 PER-1에서모두동일이형접합자 ) 이최소치인 4.2% (DAL) 의값을보인반면, 다른집단에서는최대 31.8% (UNM) 로집단간많은차이를보였다 ( 평균 =23.85%). 8개다형성유전자좌를이용한각개체별유전형을비교한결과달음산집단을제외한 143개개체중 132개의고유유전형 (unique genotype) 이확인되었다. 고유유전형을각집단내에서분석한결과운문산집단은 50개개체중 4개 (8%) 개체가유 전형이중복이었으며팔공산집단의경우 48개개체에서집단내고유유전형을보였고, 가지산집단의경우 45개개체중 6개 (13.3%) 유전형이중복이었다. 전체유전자좌당대립유전자수 (A P ) 는최대 1.5(PAL) 에서최소 1.0(DAL) 으로나타났다 ( 평균 =1.33). 각집단별로직접관찰된이형접합자 (Heterozygotes) 의값 (H O ) 은달음산집단 (DAL) 의최소 0.045에서팔공산집단 (PAL) 의최대 0.144로확인되었다 ( 평균 =0.110). 또한, Hardy-Weinberg 평형에의해예상되는이형접합자의추정비율 (H e ) 의경우, 최소 0.023(DAL) 에서부터최대 0.157(PAL) 까지확인할수있었다. Hardy-Weinberg의기대치와의유의한편차 (P<0.05) 가 22 개중 4 개 (18.18%) 에서발견되었으며, 이중두개의유전자좌는양의값을나머지두개의유전자좌는음의값을나타내고있었다 (Table 3). 이처럼양과음의값으로나뉜것과유의성이있는유전자좌의숫자가극히적은점은현재조사된꼬리말발도리의집단내의유전적조성중실제이형접합자의비율이 Hardy-Weinberg의유전적기대치와비슷한값을갖고있기때문이다. 조사된집단크기와유전자좌당대립유전자의수 (r s =0.7, spearman rank correlation; Siegel, 1959), 다형성유전자좌의비율 (r s =0.8) 및이형접합자기대치 (r s =0.8) 모두에서높은상관관계를보여주었다. 꼬리말발도리의 3개집단내에서의고정지수인 F IS 값 (0.051) 은 0에서크게벗어나지않은것으로확인되었다. 집단전체의고정지수인 F IT 값이모두크게나타나서집단내이형접합자의비율은평형을이루나종전체에서는이형접합자부족을보였다 (Table 4). 이를바탕으로집단간의유전적분화의정도 (F ST ) 를측정한결과, ( 평균 =0.223) 의값을보여 Table 2. Genetic variabilities at eight polymorphic loci and mean identity values for four population of D. paniculata. Population Pop. size N A P H O H E I UNM DAL PAL GAJ Mean 1, Estimates of genetic variation within four populations. Abbreviations: N, number of individuals examined; P, percent polymorphic loci; A, mean number of allele per locus; Ae, effective number of alleles per locus; H O, observed heterozygosity; H E, expected heterozygosity.

5 고유종꼬리말발도리의생식특성과동위효소유전다양성 523 Table 3. Allele frequencies of polymorphic loci in D. paniculata. Locus Population UNM DAL PAL GAJ GOT-2 A B PGI-2 A B C GDH-1 A B MNR-1 A B PER-1 A B C PER-2 A B PGM-2 A B C PG-2 A B Table 4. Wright(1931)'s F-statistics for eight polymorphic loci in D. paniculata. Locus No. of alleles F IS F IT F ST GOT PGI GDH MNR PER PER PGM PG Mean 집단간의분화정도가높은것을알수있다. 즉, 집단내의변이가전체변이의 77.7% 로존재한다. F ST 를이용한집단간유전자이동 (Nm) 값은 0.64로나타나집단간유전적이동량이낮음을알수있다. 각집단간의유전적거리는 ( 평균 =0.047) 의값을나타내어, 집단간차이가상대적으로낮았다. 지리적거리와유전적거리간의관계는상관관계 (r s =0.214) 가없는것으로확인되었다. Nei s(1978) genetic identity에근 Figure 3. UPGMA phenogram based on Nei's (1978) genetic identities among four populations of D. paniculata.. Figure 4. Changes in genetic diversity, total number of alleles with changes in the number of individuals of D. paniculata. 거한 UPGMA(unweighted pair-group method) phenogram 결과 (Figure 3), 대구시팔공산과언양읍의가지산의유전적거리가가장가까운것으로나타났다. 한편, 밀양시의운문산과하나의유전형으로이루어진기장군의달음산과유전적으로유사하였다. 각집단별기대이형접합율은차이를보이고, 특히팔공산집단이가장높았다. 기대이형접합율을이용하여유효집단크기 (Ne) 를간접추정할수있다. 특히, Crow and Kimura(1970) 의공식에서돌연변이율 (10 3 ) 을가장높게잡았을때, 팔공산집단의경우, 42에서부터달음산집단의 12까지나타났다. 돌연변이율 (10 7 ) 을가장낮게잡을경우에는 117,801 부터 420,560까지나타난다. 유전다양성의확보를위해선발된개체로부터유전다양성누적치를계산한결과, 전체집단을합한상태에서유전형을선발하는방식으로는약 30 번째개체에서최대대립유전자 (allele) 를얻을수있었다 (Figure 4). 고 찰 1. 생식특성수분실험결과, 꼬리말발도리는타가수정을주로하는식물로확인되었다. 인공교배가타식보다결실율이높은것은수분매개자에의한자연교배보다화분의전달효율이높았기때문으로판단된다. 높은타가수정의교배전략

6 524 韓國林學會誌제 103 권제 4 호 (2014) 을선택한식물종에서는강한근교약세가존재하는것으로알려져있다 (Charlesworth and Charlesworth, 1978; Chang and Rausher, 1999; Sipes and Wolf, 1997). 꼬리말발도리처럼완전한타가수정을하는종은자가수정 (selfing), 또는자가화합성을보이는식물보다개화기간이길며, 긴개화기간은각개체들이종자성숙에필요한자원축적을가능하게한다 (Rathcke and Lacey, 1985). 일반적으로자가수정과무성번식에의존하는종의유전다양성은유전자이동에의한재조합과타가수정 (outcrossing) 등의방식과는달리돌연변이 (mutation) 라는진화적인자에기인하며, 유전형들의생태적차이와생육지의이질성에의해국지적클론다양성이유지될가능성이높다. 꼬리말발도리의유성생식에의한개체군의도입율과무성번식에의한도입율에대한정보는없으나본연구에서관찰한바에의하면단일유전형이확인된집단의경우무성번식만이유일하게집단을유지하는생식전략이된다. 2. 유전다양성동위효소를 marker로이용한집단유전학연구가축적됨에따라분포, 생활사, 생식양식및생활형등생태적특징에따라식물종의유전다양성과유전구조에대한예측이가능해졌다 (Hamrick and Godt, 1989). 일반적으로축적된자료를이용한예측은종수준에서는지리적범주가, 집단수준에서는지리적분포범주와교배양식이잘반영한다 (Hamrick and Godt, 1996). 따라서, 특정한종에서나타나는유전다양성과유전구조는이러한축적자료와의비교를통한종의특성에대한해석이가능하다. 꼬리말발도리의경우, 이전의연구자료중, 지리적분포범위에서는고유종 (endemic) 과자가수분 (selfing) 하는종및영양번식을하는종의평균유전다양성에비해서모두매우낮은유전다양성을보였다. 따라서, 꼬리말발도리는타가수분을하는생식양식 (breeding system) 의특징을갖는종임에도불구하고매우낮은유전변이를나타낸다. 일반적으로꼬리말발도리와같이낮은유전다양성을보이는유사한고유종들은진화의과정에서생태적으로제한된작은집단으로구성되어있기때문에유전적병목현상과유전적부동에의해서유전다양성을잃기쉽다 (Bouzat, 2010). 꼬리말발도리는집단의크기가지역별로큰차이를보이며, 모든집단에서뿌리로무성번식하는것이확인되었다 (personal observation). 특히, 달음산집단은 (Table 3) 대부분의개체가하나의영양번식체 (clone) 집단일것으로추정된다. 현재확인된집단크기와유전다양성 (A, P, He) 은높은양의상관관계를보였고, 집단간의유적분화값이높게나타났다. 이처럼집단의크기와유전다양성이상관관계를갖는것은꼬리말발도리의각각의집단들이완전타가수분이라는생식양식 (breeding system) 으로인하여, 자가수분이제외된상태에서집단의규모가일정한수준이하 ( 유효집단크기 ) 로떨어질경우, 유전적부동 (genetic drift) 에의해유전다양성을잃었기때문인것으로판단되며, 실제유전자좌당대립유전자의수와이형접합자기대치모두에서높은상관관계를보여주는것은집단의급격한감소에따른유전자병목현상보다는집단내유전자부동 ( 협의 ) 이꼬리말발도리의유전다양성에영향을준중요한원인으로추정된다 (Ellstrand and Elam, 1993; Hamrick and Godt, 1996). 꼬리말발도리의경우각집단들의크기가제한적이며점유면적과크기가가장작은집단이유전다양성이전혀없는취약한클론집단이라는점이확인되었다. 꼬리말발도리는완전타가방식의생식양식을선호하지만, 현실적으로모든생육지에서좁은면적에높은밀도로유전적으로유사한개체들이고립되어있어결과적으로유효집단크기감소로인한개체간의근친근교 (biparental inbreeding) 가일어날수있다 (Coates and Sokolowski, 1992, Wagenius et al., 2010). 이러한근교는유전다양성을잃게할수있으나 (Hamrick and Godt, 1989), 목본식물과같은다년생식물의경우집단내에여러개의다른 cohort이존재할경우하나의집단이각세대별유전변이를보유하고있다. 이러한특징이무성번식과함께집단에여러세대의유전다양성을제공하는완충역할을할수있어집단의급격한유전다양성감소를방지한다 (Baker, 1989; Fiedler, 1987; Silvertown and Doust, 1993). 그러나클론만으로이루어진집단은환경적변화에대한완충능력은진화적으로는제한적이며, 이러한변화가급격한경우절멸에쉽게도달하게된다. 유전다양성의소실로인한근교약세현상등에대한세밀한연구가필요하며특히단일유전형을보인달음산집단에대한지속적인모니터링을시도할예정이다. 3. 집단간의유전분화꼬리말발도리는전체유전변이는집단간변이가약 22.3% 를나타내고있다. 이러한집단의분화정도는이전의연구축적자료중에서자가수정하는식물과자가수정과타가수정을겸하는 (mixed mating) 식물의중간값을보이고, 타가수분양식에비해집단간의분화가더높은값을보였다. 특히, PGI-2, GDH-1, PER-1, PER-2 등의유 전자좌는한두개의집단에만다양성을보이고, 나머지두, 세개집단은특정 allele에고정되어있어 (Table 3), 작은집단의크기와격리와유전적부동을통한이형접합성, 대립유전자가감쇠된것으로생각된다. 꼬리말발도리의집단간유전자이동은종자및화분의낮은이동성에의해제한되어있고, 현재의집단간의고립정도로본다면, 가지산과운문산집단을제외하고는집단간의유전적교류 (gene flow) 는불가능하다 (Figure 1). 이러한지형적특

7 고유종꼬리말발도리의생식특성과동위효소유전다양성 525 성은높은 F ST 값을갖게하며 (Wright, 1965, Slatkin, 1993), Nm 값은 0.64로최근의집단간에유전자이동은무시할수있을정도로매우낮게일어났으며, 집단간의격리가상대적으로오래전에이루어졌음을알수있다. 꼬리말발도리는개체마다종자의결실량과결실빈도가다르고종자의이동은섭식에의존하지않고순수하게바람과중력으로제한된다. 따라서종자의이동은수 m에서수십 m 내로제한되어있을것으로생각된다. 그러나화분의이동은주요화분매개충인 Lasioglossum exiliceps (Vachal) 의행동반경인수십 m 내에서주로이루어졌다. 높은밀도를갖는집단내개체들이동시에개화하는것은수분매개자의꽃에대한접근가능성을높여주며 (Rathcke, 1983), 이러한수분매개자의이동거리제한은화분의장거리이동을제한하였을것이다. 조사된집단중최소거리를유지하고있는가지산과운문산 (7.8 km) 의집단간의유전적분화가거리가훨씬먼팔공산집단 (48 km) 보다높은것으로보아가지산과운문산의집단간의유전적교류가거의없는것으로판단된다. 현재의꼬리말발도리집단은모든생육지가해발고도 m에위치하고있으며, 지리적으로최소 7.8 km에서최대 98 km이상떨어져있으며, 생육지간의환경적차이는없었다. 각집단의유전구조가지리적분포및거리와는상관관계를나타내지않으면서, 고립된집단이갖는독립적인유전적특성을가지고있었다. 고립된꼬리말발도리집단의형성과정에대한가설로는과거에각집단들이연속적으로넓게분포하다가지사적 (geological history) 변천에의해현재의생육지에제한적분포를보인다는것이다. 구체적으로환경변이가각집단들의개체군에대한사망률증가로이어져고립된집단들의유효집단의크기가줄어들어근교약세로이어졌을가능성이높다. 반대가설로는작은집단에서출발한개체들이장거리비산으로인한개체군의확장이있을수있다. 꼬리말발도리의종자구조특성상동물의먹이, 부착, 혹은자체날개로인한장거리비산에의한확장은무리한것으로판단된다. 이와같이내제적인원인에의한집단들의감소로특정한생육지조건내에서고립되거나절명되었을것으로보이며, 따라서, 집단의생존성에큰영향을준것은집단자체적인문제즉, 유전자이동, 집단의크기, 지리적격리로판단된다 (Delgado et al., 1999). 4. 보전전략고유종꼬리말발도리는경상도지역에국한되어분포하며, 각집단의크기가작고심하게분절화되어있다. 현재의희귀성에대한평가는분포면적및점유면적으로만판단된것이지만 (Chang et al., 2001), 최근발견된신불산과천성산등의집단을추가해도분포범위는늘어나지않 고점유면적만조금늘어나크게희귀성평가 (IUCN 적색목록평가방법 ) 에영향을주지않는다. 생육지의특성에대한구체적인조사는별개연구에서시도하고있으며, 현재관찰한바에의하면점유지역이제한되어있으며, 식생의차이도크지않다는점에서생육환경인자가중요한분포의제한요소로작용할수있다. Crow and Kimura(1970) 의공식으로부터추정된꼬리말발도리집단의유효집단추정치 (Ne) 는최대 42로이값은전체집단을합한상태에서최대대립유전자 (total number of alleles) 에도달하는데 30개체라는값보다는높았다 (Figure 4). 팔공산집단의경우, 최대유전다양성을얻기위해서는유전적으로다른 30개체이상의서로다른유전형의개체선발이필요하나, 이형접합자의수를유지하고유전부동을고려한유효집단크기로보전에는최소 42 개이상의개체가필요하다는것이다. 42개개체는이론적인유효크기에의한이론적숫자이며, 30개는 8% 의중복클론을고려한실제유전형이다른개체를얻기위한숫자로차이가있다. 또한, 각집단의유효집단유지를위해서는최대대립유전자의숫자를늘리는방향이필요한데, 유전다양성이낮은집단의경우에는현지내보전을위해다른집단의개체를확보한이식이필요하다. 즉, 다양성이높은팔공산집단을중심으로다른집단의다양한유전형개체와상호교배를통해소위집단간교배를통한유전다양성증가가필요하다. 희귀식물의현지외보전을위한이식 (transplantation) 은집단을최소생존가능크기로유지하거나, 국지적유전다양성의향상에도움이되는관리방안으로인식되고있다 (Fahselt, 1988; Aavik et al., 2012). 그러나서로이질적인집단을섞어서이식할경우가장문제가되는부분은타식약세 (outbreeding depression; Frankham et al., 2010) 현상이다. 타식약세의원인은상대적으로유전적거리가먼집단내에서지역적응에따른분화가심화된경우나, 혹은염색체분화에의한집단간이질화현상이심화된경우인데 (Allendort et al., 2013), 현재꼬리말발도리의경우, 이런원인요소와는관련이없다고판단되며, 실제집단내에서상당부분클론번식을하고있어타식약세에의한소멸의가능성은거의없다. 10년간의지속적인모니터링의결과 (personal observation), 현재의 4개집단은모두증감없이유지되는것으로확인되었고, 최근추가로발견된 2개집단모두국공유림내에존재하고있어생태적인원인에의한소멸가능성은없는것으로판단된다. 그러나이들집단에대한현지내보전을위해서는지속적인모니터링작업을통한장기간의생존성분석이필요하며, 미선나무수준의보호지정및생육지보전이필요하다 (Given, 1994; Chang et al., 2001).

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