Hereditary Flashcards
The study of hereditary. It deals with the structure, function, distribution and variation of genes.
Genetics
The process of transmission of traits from one generation to other or from parent to offspring.
Hereditary
The physical and functional unit of hereditary.
Heritable (transmissible).
Gene
A segment of DNA that codes for the production of a specific protein or trait.
Gene
Located at the specific region of the chromosome.
Gene
an inherited set of mental and bodily characteristics.
Trait
controlled by the genes and environment.
Trait
Types of Trait inherited
Physical traits
Behavioral traits
the specific location of gene or DNA sequence on a chromosome. A fixed position.
Locus (plural loci)
Alternative form or variant of a gene
Allele (gene pair)
Each chromosome has a pair genes that located at the same position.
Inherited from father and mother.
Allele (gene pair)
the allele pair is similar
“PURE BREED” organism.
Homozygous
In a pair of allele, one allele is fully expressed in the phenotype while the other is masked.
Dominant allele
the allele pair is different
“HYBRID” organism.
Heterozygous
allele is depicted in UPPER CASE letter.
Dominant allele
this allele is completely masked or hide in the phenotype.
Recessive gene
only expressed in phenotype when inherited homozygous.
Recessive gene
depicted in lower case letter
Recessive gene
2 alleles are both expressed in the phenotype.
Codominant gene
Depicted in both capital letters
Codominant gene
example of co-dominant genes in human
ABO blood
HLA tissue type
The genetic code of an individual that is heritable.
Genotype
Combination of alleles responsible for the physical trait.
Genotype
The expression of genotype that is observable
Phenotype
Influenced by genotype and environment .
Phenotype
The physical trait or appearance of an individual.
Phenotype
Austrian scientist an Augustinian friar.
Father of Modern Genetics.
Gregor Johann Mendel
He studied the inheritance of trait on pea plant, thus creating his Law of Inheritance or the “Mendelian Inheritance”
Gregor Johann Mendel
States that the genes is the basic unit of hereditary specifically located in a chromosome and are transferred from parents to offspring.
Law of Discrete Unit of Characters
In a heterozygous gene pair or allele, the one that expressed is dominant and the other that is masked is recessive.
Law of Dominance
A gene pair from a parents segregates or separates during gametes formation.
Only one gene is received by the sperm or egg cell from the parent cell
Law of Segregation
Alleles/Genes for different trait will be passed on to the offspring independently which result to a new combination of traits.
Law of Independent Assortment
a diagram that used to predict an outcome of a particular cross or breeding experiment.
PUNNETE SQUARE (criss-cross method)
It is a summary of every possible combination of maternal and paternal allele for each gene being studied.
PUNNETE SQUARE (criss-cross method)
Inheritance patterns that do not follow the Mendel’s law of Inheritance.
Non –mendelian inheritance pattern
PUNNETE SQUARE is Named after a British geneticist
Reginald Punnett.
5 Non –mendelian inheritance pattern
Incomplete dominance
Codominance
Pleiotropy
Epistasis
Polygenic inheritance
The phenotype of the heterozygous offspring is somewhere in between the 2 homozygous parents.
Mix or blend of 2 alleles.
Incomplete dominance
Both allele are equally expressed in the phenotype.
Codominance
A single gene expressed a multiple traits.
Pleiotropy
A single gene affect several phenotypic characteristics
Pleiotropy
example of Pleiotropy
sickle cell disease and phenylketonuria
One gene controls the expression of the other different gene.
Epistasis
One gene masked or modifies the phenotypic expression of another gene
Epistasis
example of Epistasis
red hair color and albinism
A trait is controlled not only by a single gene but through multiple interaction of many genes
Polygenic inheritance
2 or more genes controlled for one trait of characteristics
Polygenic inheritance
example of Polygenic inheritance
Skin color, hair color, eye color and height.
At least 4 genes are involved in melanin production, combination of these genes produced degree of pigmentation.
Polygenic inheritance
Can occur in both sexes, and can be transmitted by either parents.
Only 1 mutated gene is need to develop or manifest the disease.
E. g. Huntington disease and Marfan syndrome.
Autosomal dominant
Most common inheritance pattern of genetic disease.
Parent is either affected or carrier of the disease.
2 mutated genes are need to manifest the disease.
E. g. Cystic fibrosis and sickle cell anemia
Autosomal recessive
Mutation in the X chromosomes of both sexes.
Both male and female are affected.
Male is more severe than female since male has only one X chromosome.
E.g. Rett syndrome, Rickets, Alport syndrome.
X-linked dominant
Inheritance pattern is from father- son only.
Y-linked
E.g. hypertrichosis- growth of hair on the outside rim of the ear. Webbed toes- webbed-liked condition between 2nd and 3rd toes.
Y-linked
E.g. Colorblindness, Hemophilia A, Duchenne muscular dystrophy.
X-linked recessive
inherited through the female line. Inheritance is from mother to all offspring and subsequently by her daughter. Both sexes are affected but only the daughter can pass the mutation.
Mitochondrial inheritance
Diabetes mellitus
Leber’s hereditary optic neuropathy- eye disorder
Neuropathy, ataxia, retinitis pigmentosa, and ptosis (NARP)-dimentia
Mitochondrial inheritance
Caused by several genes.
Not consider as genetic disease in nature.
Development of the disease are influenced by environmental factors.
E.g. malignancies, diabetes, autoimmune disorders, hypertension and heart disease.
Polygenic/multifactorial
