STR

Is the combination of SNPs and STRs superior to SNPs alone for prenatal paternity testing?

親子鑑定　NIPPT　DNA鑑定　科学的根拠　原則

↓今すぐDNA出生前親子鑑定を予約する↓

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As to whether the combination of SNPs and STRs is superior to SNPs alone for prenatal paternity testing, the following points need to be considered

SNP and STR characteristics

1. SNP（Single Nucleotide Polymorphism）

  • Features: SNPs are variations of a single base in a DNA sequence and are present in the human genome in the millions; analysis of SNPs is usually carried out in an automated, high-throughput manner, allowing large-scale analysis.
  • Advantages: because they are present at very high frequencies, they can be analyzed with high accuracy using a number of genetic markers in paternity testing. In addition, SNPs have a low mutation rate, which makes it easy to obtain stable results.
  • Limitations: due to the low information content of each SNP, a very large number of SNPs need to be analyzed and may not provide sufficient information in certain situations (e.g. appraisals between very close relatives) when used on its own.

2. STR（Short Tandem Repeat）

  • FEATURES: STRs are short repeat sequences in DNA, with the number of repeats varying from individual to individual. This diversity makes STRs a powerful tool in analysis.
  • Advantages: STRs are highly polymorphic and powerful for individual identification. In paternity testing, even a small number of STR markers can provide highly accurate results, especially for distinguishing between genetically close individuals.
  • Limitations: due to the relatively high mutation rate of STRs, they sometimes do not match between parents and children, and the risk of misclassification may be slightly higher than for SNPs.

Combination of SNPs and STRs

1. Complementary benefits:

  • Combining SNPs and STRs: the stability of SNPs combined with the high discriminatory power of STRs can compensate for the weaknesses of each technique. For example, SNPs provide a great deal of information, while STRs can determine more specific parent-child relationships due to their high polymorphism.

2. High accuracy determination:

  • The use of both SNPs and STRs increases the accuracy of parent-child identification in particular.This provides more reliable results and further reduces the risk of misclassification.

3. Advantages in special cases:

  • SNPs alone can be difficult to discriminate in the identification of genetically very close relations (e.g. siblings or cousins), but combining STRs can solve this problem.
Weeks available for inspectionAccuracy between close relatives.Inspection possible location
STR aloneFrom 8 weeks’ gestation.○Hiro Clinic
SNP stand-aloneFrom 7 weeks’ gestation.△other facilities
SNP + STR combinationFrom 6 weeks’ gestation.◎Hiro Clinic

Conclusion

The combination of SNPs and STRs is considered superior to SNPs alone in prenatal paternity testing. The combination of the two provides increased accuracy and reliability, especially in the elucidation of complex genetic relationships. This enables accurate determination of parent-child relationships and is the optimal approach in prenatal paternity testing.

医師監修 監修日：2024年8月22日

岡 博史 （おか ひろし）

医師・医学博士 ／ ヒロクリニック統括院長

YouTubeチャンネルなどを通じて、遺伝子やNIPT（新型出生前診断）についてわかりやすく発信しています。

略歴

  • 1996年 慶應義塾大学医学部 卒業
  • 2004年 慶應義塾大学 医学博士号 取得
  • 2005年 慶應義塾大学 皮膚科学教室 助手
  • 2008年 ヒロ皮フ形成クリニック 開業
  • 2009年 医療法人社団福美会 理事長
  • 2015年 医療法人社団福美会 理事

資格・所属

  • CAPラボディレクター
  • 日本皮膚科学会 皮膚科専門医
  • 日本医師会 産業医
  • 東京衛生検査所 指導監督医

発信・関連リンク

この記事は、 ヒロクリニックNIPPTの編集・監修体制 にもとづき、資格を持つ医師が内容を確認しています。

医師監修 監修日：2024年8月22日

堤 修一 （つつみ しゅういち）

医師・医学博士 ／ ヒロクリニック博多駅前院 院長

略歴

  • 1993年 東京大学医学部医学科 卒業
  • 2016〜2019年 東京大学先端科学技術研究センター 准教授

発信・関連リンク

この記事は、 ヒロクリニックNIPPTの編集・監修体制 にもとづき、資格を持つ医師が内容を確認しています。

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Supervisor of the article

Dr. Hiroshi Oka

Director of CAP Laboratory

Graduated from Keio University, Faculty of Medicine

Doctor of Medicine

Medical Doctor