Biology Reference
In-Depth Information
CM F
M
TC UD1 UD2 UD3
(a)
(b)
Figure 1.3
(a) The first ever DNA fingerprint, produced in Alec Jeffreys' laboratory on the 10
th
September 1984. It shows the banding pattern from a mother, child, and father: the bands in the
child's profile can be attributed to either the mother or the father. (b) Profiles from a mother, a
tested child (TC) (Immigration Officials in the UK did not believe that the boy was the biological son
of the mother) and three of the mother's undisputed children (UD 1-3): the results demonstrated
that the tested child was indeed the biological son of the woman and was therefore allowed to
stay in the UK [2]. (Images provided by Sir Prof Alec Jeffreys, Department of Genetics, University
of Leicester, UK)
With the first DNA fingerprints the multi-locus probes (MLPs) detected several
minisatellite loci simultaneously, leading to the multiple band patterns. While the
multi-banded fingerprints were highly informative they were difficult to interpret.
New probes were designed that were specific to one locus (single locus probes, SLPs)
and therefore produced only one or two bands for each individual [74] (Figure 1.4).
Minisatellite analysis was a powerful tool but suffered from several limitations: a
relatively large amount of DNA was required; it would not work with degraded DNA;
comparison between laboratories was difficult; and the analysis was time consuming.
Even so, the use of minisatellite analysis, using SLPs, was common for several years
[75] until it was replaced by polymerase chain reaction (PCR)-based systems.
A critical development in the history of forensic genetics came with the advent
of a process that can amplify specific regions of DNA - the PCR (see Chapter 5).
The PCR process was conceptualized in 1983 by Kary Mullis, a chemist working
for the Cetus Corporation in the USA [76]. The development of PCR has had a
profound effect on all aspects of molecular biology including forensic genetics, and
in recognition of the significance of the development of the technique Kary Mullis
was awarded the Nobel Prize for Chemistry in 1993.
