Com. v. Blasioli

• Decision Date: 16 June 1998
• Citation: 713 A.2d 1117,552 Pa. 149
• Parties: COMMONWEALTH of Pennsylvania, Appellee, v. Donald J. BLASIOLI, Appellant.
• Court: Pennsylvania Supreme Court

Page 1117

713 A.2d 1117

552 Pa. 149

COMMONWEALTH of Pennsylvania, Appellee, v. Donald J. BLASIOLI, Appellant.

Supreme Court of Pennsylvania.

Submitted March 9, 1998.

Decided June 16, 1998.

[552 Pa. 151] Timothy Paul Dawson, Adamsburg, for Donald J. Blasioli.

John W. Peck, Wayne B. Gongaware, Greensburg, for the Com.

Before FLAHERTY, C.J., and ZAPPALA, CAPPY, CASTILLE, NIGRO, NEWMAN and SAYLOR, JJ.

OPINION

SAYLOR, Justice.

We allowed appeal to determine whether evidence of statistical probabilities calculated using the product rule is admissible at trial in a criminal case to assist the trier of fact in assessing the probative significance of a deoxyribonucleic acid ("DNA") match. We agree with the trial court and the Superior Court that the product rule, as applied in DNA forensic analysis, is generally accepted in the relevant scientific communities and that such evidence therefore meets the standard for admissibility.

In May, 1993, J.D. was assaulted and raped. The crimes occurred late at night, after she departed a neighborhood tavern in Greensburg, Pennsylvania, and while she was walking home to the city of Jeanette along a poorly-lit road. During the attack, the assailant held his hand over J.D.'s eyes, and J.D. closed her eyes throughout the encounter for fear that her assailant would take her life if she saw his face. The assailant smoked a cigarette before departing the scene.

J.D. contacted the police and was taken to the hospital, where medical professionals conducted a rape examination and collected seminal fluid. The Pennsylvania State Police recovered various items from the scene of the attack, including a fresh Bel-Aire cigarette butt, which was tested and found to have been smoked by an individual having type A blood.

In September, 1993, an investigating officer visited Appellant Donald J. Blasioli ("Blasioli") at his home and informed him that an investigation was in progress related to a separate sexual assault that had occurred in the previous month. Upon request, Blasioli provided a saliva sample, but declined to provide hair and blood samples. During the course of the interview, Blasioli admitted that he smoked Bel-Aire cigarettes.

Subsequent testing of Blasioli's saliva sample indicated that he had type A blood. Based upon this information, the police obtained a warrant authorizing them to obtain samples of Blasioli's hair and blood. DNA testing performed at the Pennsylvania State Police laboratory resulted in a determination of a match between Blasioli's blood sample and the semen sample obtained from J.D. immediately after the crimes. Based upon this evidence, Blasioli was arrested and charged with rape, indecent assault, simple assault and unlawful restraint.

Prior to trial, the Commonwealth disclosed its intent to present testimony concerning both the results of the DNA testing and certain probabilities derived from those tests using statistical methods known as the product rule and the ceiling principle. Specifically, the Commonwealth sought to introduce expert testimony that: the probability of a random occurrence in the general population of a DNA profile matching both Blasioli's and the crime sample, calculated using the product rule, was one in 10 billion; and the probability calculated using the ceiling principle was one in 30 million. After a pre-trial hearing pursuant to Frye v. United States, 293 F. 1013 (D.C.Cir.1923), the trial court ruled that the evidence met the standard of admissibility for novel scientific evidence.

At trial, J.D. testified to the circumstances of the crimes, but was unable to identify Blasioli as the perpetrator. The Commonwealth presented its scientific evidence through the testimony of expert witnesses, and Blasioli presented an expert to refute the Commonwealth's evidence. The jury found Blasioli guilty of all charges, and he was sentenced to concurrent terms of four to eight years imprisonment on the rape charge and six to twelve months on the remaining charges. On direct appeal, the Superior Court affirmed, see Commonwealth v. Blasioli, 454 Pa.Super. 207, 685 A.2d 151 (1996), and this appeal followed.

In determining whether novel scientific evidence is admissible in criminal trials, Pennsylvania courts apply the test set forth in Frye, 293 F. at 1013. ¹ See Commonwealth v. Topa, 471 Pa. 223, 231, 369 A.2d 1277, 1281 (1977) (adopting the Frye test). Pursuant to Frye, to be admissible, such evidence must have gained general acceptance in the relevant scientific community. See Commonwealth v. Zook, 532 Pa. 79, 98-99, 615 A.2d 1, 12-13 (1992) (citing Commonwealth v. Topa, 471 Pa. 223, 230, 369 A.2d 1277, 1281 (1977)), cert. denied, 493 U.S. 873, 110 S.Ct. 203, 107 L.Ed.2d 156 (1993). This Court has generally required that both the theory and technique underlying novel scientific evidence must be generally accepted. See generally Crews, 536 Pa. at 522, 640 A.2d at 402 (finding general acceptance with respect to theories and methods of DNA forensic analysis).

In this case, Blasioli attacks the validity of the application of a principle of statistical probability to DNA forensic analysis. Blasioli and the Commonwealth are in apparent agreement that the scientific communities relevant to this issue include the disciplines of population genetics, human genetics and population demographics. ²

In addressing the merits of the parties' arguments, a brief description of the scientific principles and procedures applied in DNA analysis is necessary. ³ DNA is genetic material found in most types of cells of the human body, including white blood cells and cells contained in semen and hair follicles. ⁴ DNA constitutes the primary element of an organism's total genetic information, known as its genome. In the process of cellular division, DNA functions essentially as a template, providing a blueprint for resulting cells. DNA also directs the construction of specific proteins that comprise the structural component of cells and tissues, as well as the production of enzymes necessary for essential biochemical reactions. As such, DNA determines an organism's unique physical composition. See generally MORIARTY, SCIENTIFIC EVIDENCE IN CRIMINAL TRIALS, supra note 2, § 11.11, at 11-8-10; SUTTON, INTRODUCTION TO GENETICS, supra note 2, at 29-60; Smith & Gordon, Admission of DNA Evidence, supra note 2, at 2467 (citing PELCZAR, MICROBIOLOGY, supra note 2, at 350-400 (explaining the structure and characteristics of DNA)); Kaye, DNA Evidence, supra note 2, at 107 (citations omitted).

A DNA molecule consists of strands in the shape of a ladder, twisted into a characteristic shape resembling a spiral staircase, which is described as a double helix. Each side of the ladder is composed of repeated sequences of phosphate and sugar molecules, with a nitrogen-containing chemical called a base extending toward the opposite side to join a complimentary base, together forming a rung of the ladder. ⁵ Each unit of a strand, containing one sugar molecule, one phosphate molecule and one base, is called a nucleotide. See MORIARTY, SCIENTIFIC EVIDENCE IN CRIMINAL TRIALS, supra note 2, § 11.11, at 11-9; Smith & Gordon, Admission of DNA Evidence, supra note 2, at 2465-66 (citing PRESCOTT, MICROBIOLOGY, supra note 2, at 193); Kaye, DNA Evidence, supra [552 Pa. 156] note 2, at 107 (citations omitted); see generally Armstead v. State, 342 Md. 38, 673 A.2d 221, 227 (1996)(citing BEADLE, LANGUAGE OF LIFE, supra note 2, at 193-94).

Each pair of nucleotide bases joined to form the rungs of the DNA ladder is called a base pair, of which there are over three billion in any single DNA molecule. It is the unique, repeating sequences of the base pairs along the double strands of DNA that provides the instructions for individual human characteristics. A gene, the fundamental unit of heredity, is a functional unit of DNA containing the base pair sequence responsible for a particular characteristic. The human genome is estimated to comprise at least 100,000 genes. Alternative forms of genes are known as alleles, ⁶ and the position of a gene or allele on a chromosome is known as its locus. See generally MORIARTY, SCIENTIFIC EVIDENCE IN CRIMINAL TRIALS, supra note 2, § 11.11, at 11-9; Smith & Gordon, Admission of DNA Evidence, supra note 2, at 2466 (citing 1996 NRC REPORT, supra, note 3, at 13).

Large segments of human DNA are the same from person to person, accounting for human characteristics that are generally shared. Indeed, from the sequence of the 3 billion base pairs, only about 3 million differ from one individual to another (except in the case of identical twins, who have identical DNA). See Smith & Gordon, Admission of DNA Evidence, supra note 2, at 2466 (citing 1996 NRC REPORT, supra note 3, at 63). It is the existence of such differences in the sequencing of base pairs, known as "polymorphisms," that provides the basis for DNA identification. ⁷ See MORIARTY, SCIENTIFIC EVIDENCE IN CRIMINAL TRIALS, supra note 2, § 11.11, at 11-9; Smith & Gordon, Admission of DNA Evidence, supra note 2, at 2467 (citing 1996 NRC REPORT, supra note 3, at 61); see also Armstead, 673 A.2d at 227-28 (citing same).

The length of each polymorphism is determined by the number times a particular base pair sequence is repeated along the chromosome. Stretches of DNA along which a short nucleotide sequence is repeated are known as "variable number tandem repeats" or "VNTRs." Because of their length, such discrete portions of a DNA sample's patterned chemical structure are most easily capable of identification, and much of DNA forensic analysis relies upon loci containing these polymorphisms. See MORIARTY, SCIENTIFIC EVIDENCE IN CRIMINAL TRIALS, supra note 2, § 11.11, at 11-9-10; Smith & Gordon, Admission of DNA Evidence, supra note 2, at 2467 (citing 1992 NRC REPORT, supra note 3, at 61); Kaye, DNA Evidence, supra note 2, at 108-09 (citations omitted).

DNA forensic analysis begins with the...