2. INTRODUCTION:
What is genetics:
Genetics is the study of genes, genetic variation, and heredity in living organisms.
It is generally considered a field of biology, but intersects frequently with many other
life sciences and is strongly linked with the study of information systems.
3. HISTORY OF GENETICS:
Gregor Johann Mendel:
Gregor johann mendel was Augustinian priest and scientist and is often called father
of genetics for his study of inheritance and of certain traits in pea plants
Hugo de Vries :
In 1889 Hugo de Vries came up with the name “(pan)gene” for after postulating that
particles are responsible for inheritance of characteristics.
William Bateson:
Term “Genetics” was coined by William Bateson in 1995.
4. BASIC CONCEPTS OF GENETICS:
Cell division:
Mitosis (somatic cell)
Meiosis(germ cell)
Nucleus : contains genetics materials .
DNA: genetic materials 4 bases nucleotides (A,G,C,T).
Gene: functional unit of heredity sequence of 4 nucleotides .
Chromosome: linear DNA molecule .
Mendelian Genetics: transmission genetics .
Molecular Genetics: hereditary material .
5. HEREDITY:
Heredity:
Heredity is the passing down the traits from parents of offspring
The hereditary information is present in the gametes of the parents.
Thus gametes constitute the link between one generation to the next and pass
On the maternal and paternal characters or traits of the offspring .
6. IMPORTANT TERMS
Chromosome: it’s a thread-like structure in the nucleus of a cell formed of DNA
Which carries the gene.
Gene: it’s a unit of DNA on chromosome.
dominant gene.
recessive gene.
Genotype: it’s the descriptions of gene present in an organism.
Phenotype: it’s the characteristics which is visible in an organism.
First filial generation or F1 generation.
Second filial generation or F2 generation.
7. MENDEL’S EXPERIMENT
There are many low of Mendel’s :
Law of segregation .
Low of independent assortment.
Transmission of traits .
Sex determination.
Acquired traits.
Inherited traits.
8. VARIATION:
Variation:
The differences in the characters among the individuals of a species is called
Variation .
There are many kinds of variation in human species like:
different eye colour .
height,chin .
hair colour ,hair type .
different complexions .
nose .
9. ACCUMULATION OF VARIATION:
The significance of variation shows up only if it continues to be inherited by
the offspring for several operations .
The great advantage of variation in species is that it increases the chances of
its survival in a changing environment .
10. Variation maybe inherited or acquired .
Inherited variations results from the activity of genes
Exmple:skin colour ,blood group.
Acquired variations results from an individuals activities or nutrition
during a life
Time .
Exmple:mental skill, body building.
13. EVOLUTION
EVOLUTION: it’s the sequence of gradual changes which take places in the
Primitive organisms over millions of years in which new species are produced.
There are some important sources which provides evolution are
homologous,analogous,organs,fossils .
14. HOMOLOGOUS ORGANS
Homologous organs: organs which have same fundamental structures but different in
function .
Exmple: hands of human, wings of birds.
16. FOSSILS
The remains of dead animals or plants that lived in the remote past are known
As fossils.
Fossils are obtained by digging into the earth .
Example: ammonite,trilobite,dinosaur.
