Genetics 2
The insertion of genetically altered or normal genes into cells using
recombinant DNA technology, to replace the defective genes that
cause genetic disorders.
gene therapy
Condition resulting from a change in a gene or the number of
chromosomes.
genetic disorder
Modern techniques or processes used to artificially alter the genetic
information in the chromosome of an organism. The process
involves the following:
1. isolation of gene
2. cutting (restriction)
3. transformation (ligation), introduction of base sequence
changes
4. expression.
The DNA from individuals is analysed and a DNA profile is made. This
is similar to a bar code. A DNA profile is unique for each individual.
Profiles can then be compared for identification purposes.
New combinations of genes (genotypes) that have arisen in offspring
as a result of gene mutation, chromosome mutations or the use of
recombinant DNA technology.
The study of the structure and function of genes; the mechanisms of
inheritance and variation; and the transmission of traits or
characteristics from one generation of plants or animals to another.
genetic
engineering
genetic
fingerprinting
genetic
recombinations
genetics
Tests to identify the presence of a specific gene or the presence or
absence of changed or harmful genes possessed by an individual.
genetic screening
All the genes of an individual or all the genes possessed by members
of a population or species.
genome
Genetic makeup of an individual or the genes that they inherit, e.g.
Tt.
genotype
Spontaneous change (mutation) that has occurred in a gamete. This
change can be passed on to the offspring produced.
germ cell
mutation
One of the purine nitrogenous bases present in DNA and RNA.
Known by its abbreviation G.
guanine
The natural law or property of organisms whereby their offspring
have various physical and mental traits of their parents or ancestors,
heredity
i.e. certain traits, controlled by a genetic code within the
chromosomes, are transmitted from one generation to the next.
An individual that does not breed true (true-breeding)for a particular
heterozygote /
trait, since it has dissimilar genes for the trait, e.g. Nn, Tt, i.e. It has
heterozygous
both the dominant and recessive genes.
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Pair of chromosomes in diploid cell, same length and shape and
contain genes at the same position (locus) for the same traits.
homologous
chromosomes
An organism that breeds true (true-breeding) for a particular trait,
because it possesses a pair of similar genes for the trait, e.g. TT or tt.
homozygote /
homozygous
A project undertaken by scientists worldwide to try and establish the human genome
DNA sequence of the human chromosomes.
project
A heterozygous individual. OR
A crossbred animal or plant, i.e. one arising from a cross between
two different species, races or varieties.
hybrid
To receive genetic information from one’s parents.
inherit
The qualities, characteristics or traits an organism possesses as a
result of receiving them from its parents or ancestors.
inheritance
Also known as junk genes. They are pieces of DNA that do not code
for a protein and seem to have no function other than to separate
genes.
interons
Diagram of chromosomes in a cell arranged in pairs and in order of
size.
karyogram
Character/make-up of cell nucleus determined by the type of
chromosomes present.
karyotype
This states that during gamete formation each member of a pair of
genes may combine randomly with either of another pair.
law of
independent
assortment /
Mendel's 2nd Law
This states that characters (traits) are controlled by pairs of genes
(e.g. Tt) that separate (segregate) at gamete formation. Each gamete
carries only one gene for the trait. At fertilisation the new organism
will have two genes for each trait – one received from each parent.
Genes located on the same chromosome that are not separated at
gamete formation and are inherited together. Genes never
separating, seldom occurs.
law of segregation
/ Mendel's 1st
Law
linkage
The position of a gene on a chromosome.
locus
A type of ribonucleic acid found in the nucleus (10%) and cytoplasm
(90%). It carries the instructions for protein manufacture from the
DNA in the nucleus to the ribosomes in the cytoplasm, where
protein is made.
mRNA (messenger
RNA)
A genetic cross which examines the transmission of one trait, e.g.
height, eye colour, etc.
monohybrid cross
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More than two forms of a gene controlling one trait, e.g. in blood
groups there are four (pheno)types (A, B, AB and O) controlled by
three genes (A, B and O).
multiple alleles
A substance or agent capable of causing or bringing about a
mutation, e.g. UV light/radiation, x-rays and certain chemicals.
mutagen
A spontaneous change in the sequence of nitrogenous bases in a
gene or a chromosome.
mutation
Nitrogen containing compound that forms nucleotides, which are
the building blocks of DNA and RNA. Five types: adenine (A),
cytosine (C), guanine (G), thymine (T) and uracil (U).
DNA is found in other organelles of the cell apart from the nucleus,
e.g. mitochondrial DNA and chloroplast DNA. These organelles play
no part in sexual reproduction but are present in the female
gametes. At fertilisation it is only the nucleus of the male gamete
that fuses with the egg. All the mitochondrial DNA you possess you
got from your mother, and she got hers from her mother, and so on.
As a result there are very few different types of mitochondrial DNA.
nitrogenous base
non-nuclear
inheritance
Two types, RNA and DNA. Long chains of nucleotides found in
cytoplasm and nucleus of all cells, plant and animal.
nucleic acid
Made up of:
1. a phosphate group
2. one five carbon sugar: deoxyribose (C5H10O4) or ribose (C5H10O5)
3. one nitrogen base: adenine (A), cytosine (C), guanine (G),
thymine (T), uracil (U).
nucleotide(s)
Using transgenic farm animals in the production of pharmaceuticals,
e.g. sheep to produce factor VIII.
pharming
Physical appearance of an individual as a result of the interaction of
the genotype with the environment.
phenotype
Small circular piece of DNA found in bacteria and yeast. Often
contains genes bestowing drug resistance.
plasmid
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