MODULE-11-Human-Genetics Flashcards
To determine the pattern of inheritance of man’s traits, the construction of family
history is performed.
Pedigree Analysis
It is a diagram that displays the family history of a certain trait. The affected individual whom the pedigree is discussed is called the
proband
The information from a pedigree makes it possible to determine how certain alleles are inherited: whether they are
dominant
recessive
autosomal
sex-linked
will not skip a generation.
Dominant traits
neither parent is required to have the trait since they
can be heterozygous
recessive traits
males are much more commonly affected than females
X-linked recessive traits
both males and females are equally likely to be affected
autosomal traits
Common pattern of inheritance in man 5
Autosomal dominance
Autosomal recessive
Sex-linked dominance
Sex-linked recessive
Sex-influenced
The trait for this type of inheritance never skips a generation
Autosomal dominance
Marriage between 2 affected individuals produce affected offspring
Autosomal recessive
Affected male with unaffected wife transmit the trait to daughter only
Sex-linked dominance
Affected female with unaffected husband transmits the trait to sons only; the daughters
serve as carrier of the trait
Sex-linked recessive
Gene exhibits high penetrance or expressivity in one sex
Sex-influenced
One mutated copy of the gene in each cell is sufficient for a person to be affected by an BLANK. In some cases, an affected person inherits the
condition from an affected parent.
EX - Huntington disease
Marfan syndrome
Autosomal dominant disorder
both copies of the
gene in each cell have mutations.
EX - Cystic fibrosis
Sickle cell disease
Autosomal
recessive
disorders are caused by mutations in
genes on the X chromosome, one of the two sex
chromosomes in each cell
EX - Fragile X syndrome
X-linked
dominant
disorders are also caused by
mutations in genes on the X chromosome.
EX - Hemophilia
X-linked
recessive
if the mutated gene
that causes the disorder is located on the Y
chromosome, one of the two sex chromosomes in each
of a male’s cells.
EX - Y chromosome
infertility
Y-linked
two different versions
(alleles) of a gene are expressed, and each version
makes a slightly different protein.
EX -ABO blood group
alpha-1 antitrypsin
deficiency
Co-dominant
also known as maternal
inheritance, applies to genes in mitochondrial DNA
EX - Leber hereditary
optic neuropathy
Mitochondrial DNA inheritance
have a total of 46 chromosomes (2n), 22 paired body chromosomes and two
sex chromosomes.
Humans
It has been found that around 4% of local clinically recognized pregnancies carry some form of trisomy.
Autosomal Aneuploidy
Among the most common trisomy are
trisomy-21 (Down Syndrome)
trisomy–18 (Edward Syndrome)
trisomy – 13 (Patau Syndrome)
The name is derived from the name of a British physician who first
described the syndrome in 1866.
J. Langdon Down
John H. Edwards and his associates first described this syndrome in 1960. The affected child is found to be trisomic for chromosome 18.
Edward’s Syndrome
is very rare.. It involves chromosomes 13, 14, and 15. This syndrome was first described by the group of Klaus Patau. A baby with missing chromosome 13 found out to have multiple malformations.
Patau syndrome Syndrome
results from the deficiency of the short arm of chromosome 5, which is due to the translocation of B/G and B/D chromosome groups.
Cri-du-chat Syndrome
deletion of a small segment of chromosome X, involving the genes for the synthesis of dystrophin.
Muscular dystrophy
is a complex of protein that work together to strengthen muscle fibers and protect them from injury as muscles contract and relax.
Dystrophin
Recipocal translocation involving chromosomes 2 and 20
Robertsonian translocation
translocation involving
chromosomes 9 and 22
Philadelphia syndrome
e is a component of lactose, which is not required in normal human development but can be used as energy source.
Galactosemia
An inborn error of metabolism that renders an individual unable to hydroxylate
phenylalanine to tyrosine
Phenylketonuria
is a hereditary abnormality that is due to errors on melanin synthesis. It is
characterized by congenital reduction or absence of melanin pigment due to errors in the
production of melanin from tyrosine
Albinism
Group of disorders that affect hemoglobin
Sickle Cell Disease
Behavioral Genetics 7
Schizophrenia
Eating Disorders
Drug Addiction
Mood Disorders
Intelligence
Alcoholism
Criminality
Characterized by cleavage of personality, and loss
of ability to organize thoughts and perception.
Schizophrenia
can be in the form of anorexia or bulimia.
Eating disorder
characterized by compulsive behavior of seeking and taking a drug despite of its known adverse effects
Drug addiction
more common in women; chronic depression interspersed with acute episodes
Mood disorders
foundation of rational behavior
not a well-defined characteristic
Intelligence
Studies showed that more
alcoholics are color blind. Alcoholism is an X-linked recessive trait
Alcoholism
A behavioral disorder that can be strongly inherited
Criminality
The name is derived from the name of a British physician (J. Langdon Down) who first
described the syndrome in 1866.
Down Syndrome
With multiple malformations;
Low- set ears, small lower jaw,
clenched fingers, deformed skull,
face, feet
Edward Syndrome
with sloping forehead, harelip,
palate, deformed face
polydactyly present
markedly mental retarded
cardiac and internal defects
Patau syndrome
Mental Retardation; slanting
eyes; mongolian eye fold; saddle
nose; swollen tongue;
underdeveloped ears; slightly
flattened face;
Down Syndrome
47,XXY
Klinefelter syndrome
45,X
Tuners syndrome
47,XXX
Triplo-X syndrome
22II + XYY
Jacob syndrome or double Y syndrome
46,XY
Hermaphroditism
