人類第21對染色體雙核苷酸重複序列長度及頻率之分佈

Differential Distribution of Dinucleotide Repeat Length and Frequency in Human Chromosome 21

許欽木(Chin-Mu Hsu) ； 陳文華(Wen-Hua Chen) ； 陳嫈嫈(Lng-Lng Chen) ； 陳啟清(Chi-Ching Chen)

《慈濟醫學雜誌》 12卷2期 (2000/06) Pp. 105-110

https://doi.org/10.6440/TZUCMJ.200006.0105

摘要

目的：微衛星DNA為一簡單重複序列，由1~6個鹼基重複多次序列片段所組成，廣泛分佈於真核生物整個基因組中，具高度變異性，常應用於遺傳標記、基因定位及族群遺傳，希望藉由分析探討雙核苷酸重複序列數量之變化，更進一步瞭解微衛星。材料及方法：本研究函由GCG程式套組協助，搜索GenBank中染色體21之DNA 序列，分析一千一百萬鹼基對，並探討雙核苷酸重複序列在此染色體所出現的頻率。結果：從資料分析結果顯示，CC/GC/GG三種雙核苷酸重複序列，在重複長度方面最短小，常在重複6次以下，而最長以AC/GT，可達到24次。雙核苷酸重複序列出現頻率可分AA/TT、AT/AG/AC/CT及CC/CG/GG等三群雙核苷酸重複序列，出現頻率相差極大，各在250~450、100~200及50以下三個範圍。各個相同重複單之雙核苷酸重複序列距離由三千至十六萬鹼基配對，二個任何重複單元之雙核苷酸重複序列之距離則只有八百鹼基配點。結論：這些不同雙核苷酸重複序列，在第21對染色體上所估的角色應有其不同之地位，其存在的意義及重要性有待更進一步研究。(慈濟醫學2000; 12: 105-110)

關鍵字

微衛星 ； 雙核苷酸 ； 第21對染色體

並列摘要

Objective: Microsatellites are elements that comprise multiple copies of a repeated unit in a range of from one to six base pairs. They are common and polymorphic in eukaryotic genomes. They have been used as genetic makers, in gene mapping, and in population genetics. Chromosome 21 is one of the smallest chromosomes and is closely related to Down Syndrome. It is important to understand the distribution of different dinucleotide repeats in chromosome 21. Materials and Methods: Using the Genetics Computing Group software, we spread of dinucleotide repeats which repeated four or more times in the 244 DNA sequences (eleven million base pairs) of chromosome 21. Results: In sequence analysis, the maximum length of the dinucleotide repeat unit CC,CG and GG was noted to be extremely low (less than six times), whereas the GA/GT dinucleotide repeat had the longest maximum length (more than 24 times). The frequencies of dinucleotide repeats in human chromosome 21 could be divided into three groups with AA/TT, AC/GT/AG/AT/CT, and CC/CG/GG in the ranges of 250 to 450, 100 to 200 and 0 to 50, respectively. The distances between each pair of dinucleotide repeat with the same repeat unit ranged from 3000 to 160000 base pairs, while the distance between any two dinucleotide repeats was only 800 base pairs. Conclusions: Based on the length and the frequency, dinucleotide repeats in human chromosome 21 can be divided into several groups. (Tzu Chi Med J 2000; 12:105-110)

並列關鍵字

microsatellite ； dinucleotide ； chromosome21