Biology Reference
In-Depth Information
FIGURE 16.6
DNA sequence.
New Developments
In the past five to ten years, new developments in genetic technologies have allowed the
steps of amplification and sequencing to be combined into so-called “high-throughput”
methodologies. These methods use technologies that “parallelize” the amplification/
sequencing process, meaning that thousands or millions of sequences are produced at
once. The advantages are multiple: the amplification/sequencing protocol does not require
you to target select bits and pieces of the genome as classical PCR does
d
though you can
if you want to
d
and it is done at such a massive scale that all bits and pieces present in
a DNA extract are amplified and sequenced at once. It was this kind of “next generation”
technology that recently was used to finish a draft sequence of a Neandertal genome in
2010 (
Green et al., 2010
).
3. Interpretation
Interpretative tools for genetic data are mathematical (statistical) in nature and allow
researchers to describe and compare their results to real and hypothetical models. Statistical
methods involve parameters and statistics. A
parameter
is a numeric quantity, usually
unknown, that describes a certain population characteristic. For example, the “population
mean” is a parameter that is often used to indicate the average value of a quantity. A concrete
example of a parameter would be the true number of individuals in Europe who died of
tuberculosis during the Middle Ages. Parameters are often estimated, since their true values
are generally unknown, in particular when the population is large enough for it to be impos-
sible to obtain data from all population members (e.g., all Europeans). A
statistic
is a quantity
that is calculated from a sample that is used to estimate a parameter.
