Embed Size (px)
Citation preview
HEREDITY AND GENETICS
Part 1
By Vijaya Sawant PMP
Oratechsolve Inc
Heredity defines biological transmission of physical and psychological traits from generation to
generation.
The field of biology that studies heredity is called GENETICS.
Traits are transmitted by Chromosomes and Genes.
Life begins as a single cell or
zygote that divides repeatedly.
© Fancy/Veer/Corbis
Genes are segments of strands of deoxyribonucleic acid (DNA).DNA forms a double spiral (HELIX) that looks like a twisting ladder.
Each “rung” on the ladder consist of 4 basic chemicals that are placed in pairs of either: Adenine and Thymine or Cytosine and Guanine
The sequence of the rungs are the individual genetic code that cause the developing organism to grow arms, wings, skin, or scales.
There are TWO types of cell division Mitosis and Meiosis
The Double Helix of DNA
Mitosis
Identical and Fraternal Twins
Monozygotic Dizygotic
Using PDA technique you can select genes like color of eyes, sex
© Fancy/Veer/Corbis
Chromosomal Abnormalities
• Abnormalities in 22nd or 23rd pairs of autosomes.
• Genetic abnormalities are caused by combinations
of genes called Multifactorial problems
© U
.P. Im
ages/iS
tockphoto
.com
/ ©
To
masz M
ark
ow
ski/iS
tockphoto
.com
Down Syndrome
It is caused by an extra
chromosome of the 21st
pair resulting in 47
chromosomes.
Children show deficits in
cognitive and motor
development.
Typically die from
cardiovascular arrest in
middle age.
Sex-Linked Chromosomal Abnormalities
Turner Syndrome (X)
1 girl in 2,500 has syndrome.
Female is shorter than average and infertile.
Cognitive deficits problems with visual-
spatial skills, mathematics and
nonverbal memory.
(XYY) Syndrome
Rare abnormality in men.
Occurs in 1 in 1,000 males.
Active in sex and sport, learning difficulties, delayed speech and difficult time with communicating.
Klinefelter Syndrome (XXY)
1 male in 500 has syndrome
Produces less testosterone
Usually have enlarged breasts
Mild retarded particularly language, Infertile
Triple X Syndrome (XXX)
1 girl in 1,000 has syndrome.
Normal in appearance
Lower than average language skills, poor memory for recent
eventsDevelopment of external
sex organ normal
Genetic Abnormalities
• A number of disorders attributed to genes:
– Phenylketonuria (PKU)
– Huntington’s Disease
– Sickle-Cell Anemia
– Tay-Sachs Disease
– Cystic Fibrosis
– Sex-Linked Genetic Abnormalities
– Blood Linked Genetic Abnormalities
Phenylketonuria (PKU)Enzyme disorder transmitted by a recessive gene affecting 1 child in 8,000.
Cannot metabolize an amino acid called
phenylalanine;
Builds up in body and impairs functioning of the
central nervous system (CNS);
Results are mental retardation, psychological
disorders, physical problems
No cure, but PKU can be detected in new born children through blood or urine analysis; if identified placed on diets low in phenylalanine within three weeks of
birth and develop normally
Huntington’s Disease
Fatal, progressive degenerative disorder
Uncontrollable muscle movements, loss of
intellectual functioning and personality change
No Cure; Half of offspring will have disorder
Sickle-Cell Anemia
Common among African American
Red blood cells take a shape of sickle
obstructing blood and oxygen supply
Impair cognitive and academic functions,
organs failure
Cystic Fibrosis
Caused by recessive gene
Fatal hereditary disease among
European Americans
30,000 Americans have disorder, 10 million more are carriers (1 in 31
people)
Duchenne Muscular Dystrophy
Duchenne Muscular Dystrophy symptoms
Genetic Bleeding Disorder
AbnormalitiesHemophilia
1 in every 4,400 live male birth in the United States.
Caused by shortage of certain clotting factors in
blood.
Spontaneous bleedingProlonged bleeding
© P
hoto
12/T
he I
mage W
ork
s
“Test-tube” babies are grown in a laboratory dish throughout their 9
month gestation period.
Misconception
