General formulas of the estimated likelihood ratio Y/X in the diagnosis of paternity of a deceased putative father

Asano, Mai; Minakata, Kumagusu; Hattori, Hideki

doi:10.1007/bf02114581

Cited by 11 publications

(1 citation statement)

References 5 publications

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“…They presumed the genotype of the putative father from the results of testing the widow (registered wife) of the putative father and their children, as well as the alleged child and the mother, in re lation to many genetic blood marker sys tems, and thus determined whether the putative father could be excluded or not. Furthermore, Asano et al [1980] derived general formulas for calculating the pa ternity probability, which were applicable to any cases where the putative father or the mother, or both, were deceased, and evaluated statistically the efficiency of the diagnosis.…”

Section: Discussionmentioning

confidence: 99%

Application of DNA Fingerprinting to Parentage and Extended Family Relationship Testing

Honma¹,

Ishiyama²

1990

Hum Hered

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For the purpose of applying DNA fingerprinting to parentage or other extended blood relationship testing, we have developed a general system for estimating blood relationship between a set of individuals. This system can be used for any blood relationship testing, even if critical family members are unavailable. A general formula for calculating the probability of such relationships based on Bayes’ theorem has been devised and the ability of DNA fingerprinting produced by Jeffreys’ polycore probe to determine the relationships has been evaluated.

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Section: Discussionmentioning

confidence: 99%

Application of DNA Fingerprinting to Parentage and Extended Family Relationship Testing

Honma¹,

Ishiyama²

1990

Hum Hered

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Paternity evaluation in cases lacking a mother and nondetectable alleles

Chakraborty

Zhong

1994

Int J Leg Med

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In parentage testing the formulae for computing paternity index and exclusion probability generally ignores the presence of nondetectable alleles at the loci tested. In contrast, it is now known that even when paternity testing is done with hypervariable DNA markers, nondetectable alleles should not be ignored. This work presents simple formulae needed with this consideration, to analyze paternity evaluation from DNA markers in cases where the mother of the disputed child is unavailable for testing. It is shown that even a modest frequency of nondetectable alleles (e.g., 2-5% per locus) may have a substantial impact on the paternity index when the child and/or the alleged father exhibits a single-banded DNA profile at a locus. Use of such formulae can generate a high probability of exclusion and a high paternity index when multiple independently segregating hypervariable DNA markers are used.

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Letter to the editor

Chakraborty

Zhong

1996

Int J Leg Med

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In a recent article, Chakraborty et al. [1] examined the effect of the presence of nondetectable alleles on the paternity index (PI) in cases where the mother is unavailable for testing. The X, Y and PI values in the six possible cases are shown in table (page 129). We have calculated the PI in the same cases using a modification of the Logic II approach [2], and the results are in agreement in the first five cases, but not in the sixth case (case f). In this case (child and alleged father are single-banded and have no shared band) we obtained a PI of r/(p i + 2r)(pj + 2r) instead of 1/4r. Intuitively, the use of 1/4r is unrealistic because if r = 0, PI becomes infinite. If r = 0, no nondetectable alleles exist in the system and the result is an exclusion (i.e. PI = 0). Reviewing this we think that in case f (for Y) there are four possible combinations (C = AiA i -AF = AjAj; C = AiA i -AF = Ajnull; C = Ainull -AF = AjAj; C = Ainull -AF = Ajnull), with a total value of PiPj(Pj + 2r)(pj + 2r), giving a PI of r/(pi + 2r)(pj + 2r) (the same value as was obtained with the Logic I! approach). This value of PI is zero when r is zero, and the greater r is, the greater is the PI, which is more realistic.This can be compared with the ABO system, in which the O allele can be considered a nondetectable allele. Therefore, the case f is the same case in which the child is A2 and the alleged father is B, giving an IP of o/(b + 2o) (a 2 + 2o), agreeing with our formulae.The correct evaluation of the paternity index (PI) in the case where the alleged father (AF) and the child (C) show single-banded patterns with no shared band (case f of Chakraborty et al.[1]), as noted by Luque and Valverde [2], is much appreciated. However, when the mother is unavailable for testing, the nonexclusion of the AF in such cases should be substantiated by testing genotypic conformity of the AF and the child at other loci, even when nondetectable alleles at a locus are well documented.There are two reasons for this. First, note that in the circumstances of case f, the PI (= r/[(pi + 2r)(p i + 2r)]) never exceeds 1, suggesting that the likelihood of observing this case under the hypothesis of true paternity of AF is never larger than that occurring by change non-exclusion alone.Second, unless the frequency (r) of nondetectable allele(s) is appreciable, the chance that both AF and C would show heterozygosity for nondetectable alleles at the locus (i.e., AF = A i -null and C = Aj -null), the only possibility indicating a nonexclusion of AF under case f, is quite small. In other words, of the four possibilities mentioned by Luque and Valverde [2], the one representing the nonexclusion of AF (AF = A i -null, C = Aj -null) constitutes a small fraction of the total frequencies of AF-C genotype pairs under case f, namely, 4piPjr 2 versus PiPj(Pi + 2r)(pj + 2r), when the AF is not the biological father of the child. Therefore, the nonexclusion of AF based on a single such locus may be error-prone, even though the calculated PI value is non-zero. References1.C...

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General formulas of the estimated likelihood ratio Y/X in the diagnosis of paternity of a deceased putative father

Cited by 11 publications

References 5 publications

Application of DNA Fingerprinting to Parentage and Extended Family Relationship Testing

Application of DNA Fingerprinting to Parentage and Extended Family Relationship Testing

Paternity evaluation in cases lacking a mother and nondetectable alleles

Letter to the editor

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