2. CONCEPT OF GENETICS
The term ‘genetics’ was introduced by Bateson in 1906. It has been derived from the
Greek word ‘gene’, which means ‘to become’ or ‘to grow into’. Therefore, genetics is
the science of coming into being.
Genetics is the study of inheritance of disease in families, mapping of disease genes to
specific location on chromosomes, analysis of molecular mechanism through which
genes can cause disease and the diagnosis and treatment of genetic diseases.
“Genetics is that branch of biological sciences, which deals with the transmission of
characteristics from parents to offspring”.
3. PRACTICALAPPLICATIONS OF
GENETICS
Understanding genetic basis of diseases
Early and effective diagnosis of genetic disorders.
Contributes toward health promotion with genetic aspect.
Prevention of genetic conditions
Management and care in genetic disorders
Genetic information and counseling
Referral services
Social and ethical issues in genetics
4. IMPACT OF GENETIC CONDITIONS
ON FAMILIES
SOCIAL IMPACT
SOCIAL IMPACT
SOCIAL IMPACT SOCIAL IMPACT
IMPACT OF
GENETIC
CONDITIONS ON
FAMILIES
5. LAWS OF INHERITANCE
1. Law of Dominance
In heterozygous individual, a
character is represented by two
contrasting factors.
Dominant Allele: The allele that is
able to express its effect.
Recessive Allele: The allele whose
effect is suppressed.
Dominant character – F1 generation
Recessive characters – F2 generation
7. CHROMOSOMALABERRATIONS
CHANGE DESCRIPTION EXAMPLE
Monosomy One chromosome is missing
Turner’s syndrome (cells in female
contain 45 chromosomes with one X
chromosome rather than two)
Trisomy One extra chromosome
Down syndrome (Trisomy 21) cells
contain 47 chromosomes
Triploidy
One extra chromosome set
of haploid genome
Cells contain 69 Chromosomes
Tetraploidy
Two extra chromosomes
sets of haploid genome
Cells contain 92 chromosomes
