Paternity Testing

What is paternity testing

• DNA testing to determine who a child’s —— might be

• Samples used include —-, —— cells, —— fluid, and —— cells

  • Latter two for baby’s DNA

father, blood, buccal, amniotic, placental

Polymorphic DNA sequences

• Alleles

  • One of two or more nucleotide sequences that contains a variant and is found at the —— place on a ——-

  • Each person has —- alleles

  • The child will share ——- allele from the mom and —— from the dad

• Markers

  • DNA sequence with a —- location on a chromosome

  • Can detect an allele of interest

• Polymorphism

  • Presence of two or more ——- forms of a specific DNA sequence present in a population

  • Different versions of the allele are present in the population

same, chromosome, two, one, one, known, variant

Polymorphic DNA sequences

• STR (short tandem repeats)

  • —— sequences that are —- throughout a DNA sequence

  • The —- of the repeats present varies among individuals … basis of paternity and forensic testing

• VNTR (variable number tandem repeats)

  • —— sequences repeated throughout a DNA sequence

• RFLP

  • Used to detect ——-

  • DNA sample if digested into ——— using one or more —— enzymes

  • The resulting fragments are then separated by —— ———

  • The presence of an STR or VNTR can either —— or —— restriction sites which will alter the —— and —— of fragments produced

    • Used to test any polymorphisms present in the father and child and compare

• SNP (single nucleotide polymorphism)

  • ——— mutation in —— nucleotide

short, repeated, number longer, polymorphisms, fragments, restriction, gel electrophoresis, add, remove, number and size, point ,one

DNA based forensic testing

• Compare polymorphisms between crime scene DNA and suspects to find an —— match

• Southern blot test

  • Hybridization method used to detect a ——- DNA sequence

• PCR

  • amplification method used to ——- a specific section of DNA

• Loci

  • Region of DNA on a ——- that contains an allele

• Random match probability

  • The likelihood that someone picked at random will have the same ——

  • Statistical comparison to see how likely a match is due to paternity/guilt rather than —- ——

exact, specific, amplify, chromosome, allele, random chance

Prenatal Paternity Testing

• Can use ——- fluid and —— cells to provide baby DNA for testing

• NIPP (non invasive prenatal paternity test)

  • Can be performed the —— trimester

  • Uses fetal DNA found in the —- of the pregnant mother

• CVS (chorionic villus sampling)

  • Takes place at 10 and 13 weeks

  • Uses tissue from the —— and carries risk of a ——-

• Amniocentesis

  • Takes place at 15-20 weeks

  • Collect amniotic fluid but carries risk of ———

amniotic, placental, first, blood, placenta, miscarriage, miscarriage

DNA based paternity testing

• Requires three sources of DNA: ——(3)—-

• Paternity index (PI)

  • relative ——- that the AF transmitted the —— ——- allele to the child at that specific locus

• Inclusion

  • AF having the —— necessary to indicate he is likely the father

  • Contains all OPA’s

• Exclusion

  • Not have any —- that could indicate the possibility of being the father

  • Does not contain the OPA

• Obligate paternal alleles

  • Alleles shared between the —— and the —— that could NOT belong to the mother

maternal paternal child, probability, obligate paternal, alleles, alleles, father, child

DNA based paternity testing: Methodology

• Southern Blot with probe

  • Uses —— specific probes to analyze the number of repeats in the polymorphism

    • Size of hybridized DNA correlates to # of repeats

  • Detects the alleles of the mother, father, and child

  • Can detect DNA ——-

• PCR amplification of TR regions

  • Amplification of loci containing the ——- regions of the DNA to determine number of repeats

  • Separation of amplicons based on ——-

    • Product Band size is related to length of repeat

loci, methylation, polymorphic, size

Paternity Index (PI)

• Compares the likelihood that the alleged father passed down the allele vs. the likelihood that a random man passed down the allele

  • Basically, determining the likelihood that the child and father matching alleles at that locus is due to —— ——-

• Formula = X/Y

  • X = chance that the AF could transmit the —— allele

    • X = 1 if the AF is ——-

    • X = 0.5 if the AF is ——-

  • Y = chance a random man of the same race could have transmitted the allele

• PI represents the Ratio of the two probabilities

  • AF is the father vs. random man is the father

  • Larger ratio = ——- evidence that AF is the real father

random chance obligate, homozygous, heterozygous, more

Resulting using PI, PPE, CPP, and CPI

• Probability of paternity Equation

  • PPE = ———

  • A PI is calculated for EACH locus

  • Result is a % … must be ——- to be accurate

• Cumulative Paternity Index

  • CPI = ———

  • This is a addition of the PI for each ——- tested when multiple loci are tested

  • Used to calculate the CPP

• Cumulative Probability of Paternity

  • CPP = ———-

  • Result is a %

  • Representative of the probability of paternity for an AF when ALL obligate paternal alleles tested at each locus are taken into account

• The more alleles matched between the father and child, the —— the probability they are the father

PI/PI+1 × 100, >99.9%, PIa + PIb + PIc, locus, CPI/CPI+1 × 100, higher

Inclusion

• Conclusion that the —- is the real father

• Confirmed by testing——- loci and performing —— calculations

  • Father must match at ——- or more loci for inclusion to be considered

AF, >20, statistical, 20

Exclusion

• AF can —— be the father

• AF does not match the child at ——- loci

not, 3 or more

Criteria >20

• A paternity test will analyze ——- or more loci

  • These are locations on the chromosomes that vary in —— among individuals and are the subject of comparison between child and father

• Result of >20 indicates the father and child matched at at least 20 loci

  • The more loci that match = the ——- the evidence of inclusion

  • Exclusion only needs ——- or more loci to NOT match

20, length, stronger, 3

Summary

• Paternity testing is a legal —- —- ——- of a parent to a child

• Applications can include ——- investigation, immigration, parentage, and clinical

• Paternity testing utilizes either ——— or —— methodologies

• We can determine paternity using the comparison of band ——- on southern blot or PCR

  • True Father should have an allele that is the same size as the OBA from the child

• We can also determine paternity using the —— —— —— equation after determining the —- of a locus

  • If testing multiple loci we also use ——- and —— equations

• The importance of paternity testing is the determine the —— of a child

chain of custody, criminal, southern blot, PCR, size, probability of paternity, PI, CPI CPP, father

Question 1: How many allele copies should the father and child share at each locus?

one

Question 2: which suspect is guilty

suspect 3

Question 3: which suspect is guilty?

suspect 3

Question 4: could suspect 3 by the criminal?

no, they do not possess every band present in the evidence

Question 5: which paternity test can be performed the earliest

A. Amniocentesis

B. buccal swab

C. Noninvasive prenatal paternity test (NIPP)

D. chorionic villus sampling (CVS)

C

Question 6: which is NOT true about souther blot and PCR

A. PCR requires less genetic material than souther blot

B. PCR can be used to determine DNA methylation

C. Probes are needed for southern blot

D. Probes are needed for PCR

B

Question 7: Who is the potential father

AF 2

Question 8: can mitochondrial DNA be used for paternity testing? Why?

No, it’s passed down by the mother and is not as specific