Transcript Genetic Disorders

Genetic Disorders
Genetic Mutations
• Because DNA controls
characteristics of a cell it must
be copied before a cell
reproduces
• Sometimes mistakes occur
during this process
• These mistakes are called
Mutations
Genetic Mutations
• Genetic mutations are
more devastating when
• Genetic mutations
can be as little as one they occur in sex cells
than body cells because
nucleotide that was
they affect the
incorrectly copied to
whole genes that are development of an entire
organism (because every
missing or added
cell that is generated gets
the error)
Mutations
• Mutations can be: deleted
genes, extra genes, disordered
genes, or moved genes
• Most are neutral
• Eye color
• Birth marks
• Some are harmful
• Sickle Cell Anemia
• Down Syndrome
• Some are beneficial
• Sickle Cell Anemia to Malaria
• Immunity to HIV
Mutagenic Agents
• The most common cause of
mutations is Mutagenic Agents
• Mutagenic agents include things
like: Radiation, Temperature
extremes, and Chemicals
• These agents alter the DNA code
by interfering with DNA
replication, and protein formation
• Sometimes it causes uncontrolled
cell division (resulting in cancer)
Chromosome Mutations
• Chromosomal mutations:
having extra chromosomes,
missing chromosomes or
broken pieces of chromosomes
that attach or are lost
• can occur during meiosis or
mitosis (ie: the chromosomes
don’t split correctly)
• Can be caused by mutagenic
agents
Chromosomal Mutations
• Cells with chromosomal
mutations often do not
survive because so much
genetic information is
missing
• If it occurs in egg or sperm
cells, it can effect the new
fertilized cell produced
(often results in death)
Types of Disorders
• Recessive Disorder: person must
receive a copy of the mutated
gene from both parents to have
disorder (eg: Sickle Cell Anemia)
• Dominant Disorder: person needs
only one mutated gene to have the
disorder (eg: Huntington’s
Disorder)
Types of Disorders Cont’d
• X-Linked Disorder: mutated gene found
on the X chromosome; more common in
males than females because females
have 2X chromosomes and males only
have 1X (eg: Color blindness)
• Chromosomal Disorder: caused by
having extra chromosomes (eg: Down’s
Syndrome)
• Multi-factorial: Many genes are involved
in the disorder (eg: Asthma)