Mutations, Genetic Engineering - SchoolRack

butterbeanscubaBiotechnology

Dec 12, 2012 (4 years and 6 months ago)

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MUTATIONS


Somatic mutations
-

genetic changes
within body cells


Germinal mutations
-

genetic changes
within sex (germ) cells passed to
succeeding generations



Mutations


Generally recessive, masked by dominant


Generally disadvantageous


Causes genetic variation



MUTATIONS

GENE MUTATIONS


new alleles that
replaces existing
gene on a
chromosome


CHROMOSOME
MUTATIONS

permanent
change in
chromosome
structure/number.
Occurs during
meiotic synapsis.



NON
-
DISJUNCTION

When a pair of

nonhomologous

chromosomes DO

NOT separate

during mitotic cell

division.


Example:

Down syndrome/

Trisomy 21



POLYPLOIDY


Cells with more than the diploid (2n) number of
chromosomes


Ex: Tetraploid (4n) plants produces more vigorous
and desirable fruits.



Chromosomal Mutations

1) TRANSLOCATION

Segment from one
chromosome is
transferred to non
homologous
chromosome


2) INVERSION


Rotation of a piece
of chromosome so
that the order of
genes is reversed


Chromosomal Mutations

3) ADDITION


Segment broken off
one chromosome
becomes attached
to homologous
chromosomes
(duplication of
some genes)

4) DELETION


Segment breaks off
one chromosome
(loss of genes)

Mutagenic Agents


Environmental factors that
cause mutations


Radiation

X
-
rays

UV light

Cosmic rays

Chemicals



Environmental Factors and Heredity


The extent of expression can be affected by heredity

1) Leaves covered light chlorophyll

2) Twins raised together and apart

3) Temperature and Himalayan rabbits



Plant and Animal Breeding Methods


Artificial selection

Individual with desirable
trait are mated to each
other to produce the
best traits


Inbreeding



Offspring with desirable
traits are mated to each
other to produce the
best traits

Plant and Animal Breeding Methods

Hybridization

combining traits to
produce hybrid
offspring



Prevention of
undesirable
mutations


Vegetative
propagation, cuttings,
grafting, bulbs,
runners

Human Heredity


Pedigree charts


Patterns of inheritance of
certain traits can be traced in
families for a number of
generations


Charts show presence or
absence of certain genetic
traits in each generation.


Makes it possible to identify
carriers of recessive genes

Genetic Diseases

SICKLE CELL ANEMIA

Misshapen red blood cells,
low O
2

capacity


PHENYLKETONURIA

Caused by missing

enzyme needed to break

down a.a. phenylalanine

http://learn.genetics.utah.edu/units/disorders/whataregd/

Genetic Diseases

TAY SACHS DISEASE


caused by missing
enzyme necessary for
metabolism of lipids in
the brain


Predominant in
Jewish Eastern
Europeans




http://learn.genetics.utah.edu/units/disorders/whataregd/

Techniques for detecting

Amniocentesis

Cells of the fetus are withdrawn

from the amniotic sac for
testing of genetic disorders


Karyotyping


procedure to make an enlarged

photo of pairs of homologous

chromosomes screens for
abnormal chromosome
numbers


Screening

Examination of blood and urine


Genetic research

Genetic Engineering/
Gene Splicing


Genes may be transferred
from one organism to
another, producing
recombinant DNA
.


Can make strains of bacteria
that can produce useful
substances like insulin,
growth hormone and
interferon.


May eventually be possible to
correct genetic defects.

Genetic Research

Cloning



Process of producing genetically identical
offspring from a single cell of an organism


http://learn.genetics.utah.edu/units/cloning/clickandclone/