| Abstract: | 臺灣目前有三種特有的鹿科動物，分別是臺灣水鹿、臺灣梅花鹿以及臺灣山羌。其中水鹿以及梅花鹿為鹿茸主要之來源，也因為這高經濟價值而有不少研究以雜交、賀爾蒙治療、改良餵食等方法嘗試提高鹿茸之產量。此外關於這些臺灣特有鹿種的型態、行為、生活習性等都有相關的研究報導，然而除了臺灣山羌之外，臺灣水鹿以及臺灣梅花鹿目前都沒有關於基因體相關的研究。了解這些鹿種的基因體訊息對於改善鹿隻相關產業之效益有一定之幫助，同時鹿科動物染色體多樣的變化是用來探討哺乳類動物核型演化的最佳材料。因此本篇研究主要就是要建立臺灣特有鹿種之G顯帶核型圖，此外更利用G顯帶以及螢光原位雜交技術對台灣特有之鹿種進行核型比較。
經G顯帶核型圖發現雄性臺灣水鹿其染色體數目為2n=62,XY，雄性臺灣梅花鹿則是2n=66,XY，而雄性的臺灣山羌則為2n=46,XY。雖然臺灣水鹿和臺灣梅花鹿兩者染色體的數目不相同，但是卻有相同的染色體臂數目。經由核型比較發現兩者有一對高度相似的中部著絲點(metacentric)染色體2號，此外彼此其餘的染色體臂皆可找到一對G顯帶核型有著高度保留相似性的染色體臂，由此可以推斷從鹿科祖先演化至現今兩個鹿種的染色體重組機制為羅勃遜易位。此外本篇研究更利用跨物種螢光原位雜交建立了印度山羌BAC clone在臺灣水鹿及臺灣山羌染色體之對應圖譜，同時結合G顯帶核型圖比較結果以及其他文獻研究結果，證實臺灣山羌從鹿科祖先演化至現今鹿種主要是經由tandem fusion的染色體重組機制，也得到台灣三種特有鹿科動物間之核型比較關係圖。
本篇研究建立了臺灣水鹿以及臺灣梅花鹿的標準G顯帶核型圖以及染色體組型，對於未來欲研究這兩個物種可以提供完善的基因體資訊，同時對於相關研究結果的標記也能以染色體組型之位置統一標準化。此外本次研究建立的印度山羌BAC clone對應台灣水鹿染色體圖譜亦提供了臺灣水鹿每對不同染色體的標記(marker)，對於未來鹿隻的研究可以作為檢測之材料。
documentation regarding the morphology, ecology, behavior, habitat, and captivity of these deer species reported. However, the genomic study of Formosan sambar and Formosan sika deer was few except of Formosan muntjac. Understanding the genomics of Formosan sambar and Formosan sika deer is a fundamental and beneficial subject for improving this agricultural resource. Additionally, the chromosomal study of deer species is a good approach to appreciate the mammalian chromosomal evolution and further to define the karyotype of the common mammalian ancestor. Based on the rationales mentioned above, the G-banded karyotypes of these Taiwan indigenous deers were established. Furthermore, the karyotypic comparisons among sambar, sika deer, and muntjac were generated by G-banding and cross-species FISH analysis in this study.
A representative Formosan sambar G-banded karyotype with 2n=62 consists of 26 pairs of acrocentric, 4 paris of meta/submeta-centric autosomes and 2 sex chromosomes, XY in male. There are 479 bands in total in the haploid set, including both the X and Y chromosomes. The karyotype of male Formosan sika deer has 2n=66 with 2 pairs of meta/submeta-centric, 30 pairs of acrocentric autosomes and 2 sex chromosomes, XY. Based on the results of comparative G-banding karyotype and cross-species FISH, Formosan sambar and Formosan sika deer had the same fundamental arm numbers (NF=70) and shared a high degree of conservation in G-banding pattern especially the metacentric autosome 2. Additionally, the meta/submeta-centric Formosan sambar chromosme 1, 3, 4 are equivalent to Formosan sika deer chromosome 17 (to 1p), 8 (to 1q), 23 (to 3p), 24 (to 3q), 28 (to 4p) and 20 (to 4q). Acrocentric chromosome 12 and 15 of sambar are equivalent to Formosan sika deer chromosome 1q and 1p. The difference of chromosome number between these two species is mainly resulting from the Robertsonian translocation. There are four different Robertsonian translocation involving 8 different chromosomal arms differentiating the karyopyte of two deer species during chromosomal evolution.
The karyotpe of Formosan muntjac is quite different from that of sambar and sika deer. The chromosome number of this species is 2n=46. The cross-species FISH result showed that Formosan muntjac chromosome 1 is equivalent to 3 Formosan sambar chromosomes (3p, 5, 1q); chromosome 2 is equivalent to 4 Formosan sambar chromosomes (12, 11, 28, 15); chromosome 3 is equivalent to 3 Formosan sambar chromosomes (17, 3q, 1p, 7) and chromosome 4 is equivalent to 3 Formosan sambar chromosomes (27, 4q, 4p). Moreover, the result showed the orientations of all are the same (terminal to centromere). This indicated that the karyotype of Formosan muntjac is formed by numerous tandem fusions during chromosomal evolution. |
