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ABNORMALITIES:ABNORMALITIES:Variation &Variation &
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Mutations1. Somatic vs. Gametic2. Spontaneous vs. induced
3. Random vs. irreversible
4. Suppressor mutation
5. Point (base substitution) vs. Frameshift(indel)
6. Transversion and Transition
7. Missense, Nonsense and Neutral
8. Repair of mutations
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Classify the following
MUTATIONS
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ypes of Chromosomal
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Genetic diseases
Chromosomal abnormalities in the baby may be inheritedfrom the
parent or may occur with no family history. Thefollowing
chromosomal problems are the most common:
aneuploidy - more or fewer chromosomes than the normalnumber,
including:
Down syndrome (trisomy 21) - cells contain three
#21chromosomes.
Turner syndrome - one of the two sex chromosomes is
nottransferred, leaving a single X chromosome, or 45 total.
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Genetic diseases
translocation - a rearrangement of a chromosome segmentfrom one
location to another, either within the samechromosome or to
another.
balanced translocation - the DNA is equally exchangedbetween
chromosomes and none is lost or added. A parentwith a balanced
translocation is healthy, but he/she may be atrisk for passing
unbalanced chromosomes in a pregnancy.
Robertsonian translocation - a balanced translocation in
whichone chromosome joins the end of another.
mosaicism - the presence of two or more chromosomeatterns in the
cells of a erson resultin in two or more cell
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Genetic diseases single
dominant - an abnormality occurs when only oneof the genes from
one parent is abnormal. If theparent has the disorder, the baby has
a 50 percent
chance of inheriting it. Examples include thefollowing:
achondroplasia - imperfect bone development
causing dwarfism.
Marfan syndrome - a connective tissue disordercausing long limbs
and heart defects.
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Genetic diseases single
recessive - an abnormality only occurs when bothparents have
abnormal genes. If both parents arecarriers, a baby has a 25
percent chance of having thedisorder. Examples include the
following:
cystic fibrosis - a disorder of the glands causing excessmucus
in the lungs and problems with pancreas functionand food
absorption.
sickle cell disease - a condition causing abnormal red
bloodcells.
Ta Sachs disease - an inherited autosomal recessive
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Genetic diseases single
X-linked - the disorder is determined by genes onthe X
chromosome. Males are mainly affected andhave the disorder.
Daughters of men with thedisorder are carriers of the trait and
have a one in
two chance of passing it to their children. Sons ofwomen who are
carriers each have a one in twochance of having the disorder.
Examples includethe following:
Duchenne's muscular dystrophy - a disease of musclewasting.
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Genetic diseases -
due to several problems, or a combined effectof genes and the
environment.
It is difficult to predict inheritance ofabnormalities caused by
multiple factors.
Examples include heart defects, cleft lip or cleftpalate, and
neural tube defects (defects in thespine or brain).
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Genetic diseases -
certain medications (always consult yourphysician before taking
any medications duringpregnancy)
alcohol
high level radiation exposure
lead
certain infections (such as rubella)
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ASSIGNMENTASSIGNMENT
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Examples of Genetic
With complete mechanism and explanation
2 per person
