The ‘overall paternity exclusion rate’ is a measure of the probability of a result indicating that a particular individual is not the biological father of a child. In other words, it indicates how certain the result is that an individual is not the father of a proposed child, e.g. in a DNA test. This indicator is important when assessing the reliability of a paternity test.

This is the probability indicated when the father is determined not to be the father.

The probability of being determined to be the father is the paternity affirmation probability.

The Paternity Exclusion (PE) rate for a single locus is calculated on the basis of the allele frequency (f) at a particular locus. The detailed process of calculation and how to obtain the overall exclusion rate using multiple loci is described below.

Calculation of paternal exclusion rates for one locus.

The paternal exclusion rate (PE) at one locus is calculated using the following formula

f = allele frequency (probability of a particular allele being found in a population)
e.g.
Suppose the allele frequency f is 0.2.f = allele frequency (probability of a particular allele being found in a population)
e.g.
Suppose the allele frequency f is 0.2.

The formula applies to:

In this case, the paternal exclusion rate at one locus is 36%.

Calculation of overall exclusion rates for multiple loci combined.

Multiple loci are usually used in DNA testing. The PE calculated at each locus can be combined to obtain an overall exclusion rate. The overall PE at several loci is calculated as follows

PE_i = exclusion rate at each locus
Overall PE = exclusion rate calculated using all loci
e.g.
There are three loci, each with a PE calculated, as follows:
PE_i = exclusion rate at each locus
Overall PE = exclusion rate calculated using all loci
e.g.
There are three loci, each with a PE calculated, as follows:

Locus 1: PE = 0.36
Locus 2: PE = 0.25
Locus 3: PE = 0.40
To calculate this as an overall PE, first calculate (1 – PE) for each locus
1-0.36=0.64,1-0.25=0.75,1-0.40=0.60
Multiply these together:

0.64 x 0.75 x 0.60 = 0.288

Next, calculate the overall PE:0.64 x 0.75 x 0.60 = 0.288

Next, calculate the overall PE:

Overall PE = 1-0.288=0.712
This means that the overall paternal exclusion rate using the three loci is 71.2%.

Key points on paternal exclusion rates

The use of multiple loci improves the accuracy of paternity exclusion.In general, the more loci used, the higher the exclusion rate.
Paternal exclusion rates often reach 99.99% or more, which gives a very high probability of indicating that he is not the father.
Summary
Calculate the paternal exclusion rate using PE = 1 – (1 – f)^2 based on the allele frequency (f) of each locus.
When combining the PEs of several loci, use

to calculate the overall exclusion rate.
Calculating at multiple loci increases the accuracy of excluding paternity.
This method allows DNA testing to determine paternity with a high degree of accuracy.to calculate the overall exclusion rate.
Calculating at multiple loci increases the accuracy of excluding paternity.
This method allows DNA testing to determine paternity with a high degree of accuracy.

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医師監修監修日：2024年9月5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9月5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

プロフィール詳細

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。

参考文献

Smouse PE, Chakraborty R. The use of restriction fragment length polymorphisms in paternity analysis. Am J Hum Genet. 1986 Jun;38(6):918-39.
Gjertson DW, Brenner CH, Baur MP, Carracedo A, Guidet F, Luque JA, et al. ISFG: Recommendations on biostatistical evaluation of patterns from post-coital and paternity analysis. Forensic Sci Int. 2007 Nov 1;172(2-3):189-92.