Genotype: the specific genetic make-up of an individual
Phenotype: the observable characteristics produced by that genetic endowment.
A persons “genotype” is like the commands in a computer software program. Some
of the directives are used on one occasion, some on another
Chromosome: is a tightly coiled molecule of deoxyribonucleic acid (DNA) that is partly
covered by protein. Would be 2 metres long of you coiled the DNA cells out
Genes: the DNA portion of the chromosomes carries heredity blueprints in units (called
genes). The many genes carried on each chromosome are like a giant computer file of
information about your characteristics, potentials, and limitations
Alleles: Alternative forms of a gene that produce different characteristics are called
Genes affect our body’s development and functioning through one general
mechanism: genes code for the production of proteins. The estimated 70,000 different
types of proteins found in a human control the structure of individual cells and all the
chemical reactions that go on within those cells, whether they are reactions necessary to
sustain the life of the cell or are changes induced only periodically by experience or
Dominant gene: the particular characteristic that it controls will be displayed; if the gene
is recessive, the characteristic will not show up unless the partner gene inherited from the
other parent is also recessive
Polygenic transmission: in a great many instances, a number of gene pairs combine their
influences to create a single phenotype trait. This action is called (polygenic
transmission), and it complicates the straightforward picture that would occur if all
characteristics were determined by one pair of genes
Recombinant DNA procedures: researchers use certain enzymes to cut the long
threadlike molecules of genetic DNA into pieces, combine them with DNA from another
organism, and insert them into a host organism, such as a bacterium. Inside the host, the
new DNA combination continues to divide and produce many copes of itself.
Gene knockout: one procedure done with animals is to alter a specific gene in way that
prevents it from carrying out its normal function. This alternation is called gene knockout
procedure because that particular function of the gene is eliminated.
Heritability Coefficient: the extent to which variation in a particular characteristic
within a group can be attributed to genetic factors is estimated statistically by a
heritability coefficient. It is easy to confuse two terms in this discussion. “Heredity”
means the passage of characteristics from parents to offspring by way of genes’
“heritability” means how much of the variation in a characteristic within a population can
be attributed to genetic differences If a characteristic has higher concordance, or co-occurrence, in people who are more
highly related to one another, then this points to a possible genetic contribution,
particularly if the people have lived in different environments
Adoption Study: in which a person who was adopted early in life is compared on some
characteristic both with the biological parents, with whom the person shares genetic
endowment, and with the adoptive parents, with whom no genes are shared.
Twin Studies: are one of the more powerful techniques used in behaviour genetics.
Monozygotic (identical) twins develop from the same fertilized egg, so they are
Approximately 1 in 250 births produce identical twins
Dizygotic (faternal): twins develop from two fertilized eggs, so they share 50% of their
genetic endowment, like any other set of brother and sisters. They occur in 125 births.
Reaction range: for a genetically influenced trait is the range of possibilities-the upper
and lower limits- that the genetic code allows. This, to say that intelligence is genetically
influenced does not mean that intelligence is fixed at birth. Instead, it means that an
individual inherits a range of potential intelligence that has upper and lower limits.
Biologically Based Mechanism: no behaviour by any organism can occur in the absence
of biologically based mechanism