Designer Genes
Purines Pyrimidines
Guanine Cytosine
Adenine Thymine
Uracil
(RNA)
Preformation theory proposes that the only male and female is responsible
for heredity. The male gamete consists of a miniature figure of man’s body
called as homunculus which is responsible for heredity. Epigenesis (C.f.wolf
(1733-1794) and K.E. Von Baer (1792-1876) said that the
different organs and tissues of adult plant and animals
developed from the uniform embryonic tissue and not from
mere growth expansion of the miniature homunculi present in
eggs / sperms. Von Baer proposed that they developed
through a sequential modification of the embryonic tissue.
This concept is universally accepted.
Mendel’s laws
Law of Dominance
This is also called Mendel’s first law of inheritance.
According to the law of dominance, hybrid offspring will
only inherit the dominant trait in the phenotype. The alleles
that are suppressed are called the recessive traits while
the alleles that determine the trait are known as the
dominant traits.
Law of Segregation
The law of segregation states that during the production of gametes, two copies of each hereditary factor segregate so that
offspring acquire one factor from each parent. In other words, allele (alternative form of the gene) pairs segregate during the
formation of gamete and re-unite randomly during fertilization. This is also known as Mendel’s third law of inheritance.
Law of Independent Assortment
Also known as Mendel’s second law of inheritance, the law of independent assortment states that a pair of traits segregates
independently of another pair during gamete formation. As the individual heredity factors assort independently, different traits
get equal opportunity to occur together.
Sanger sequencing
1. Denaturation and Annealing
Sanger sequencing begins by separating the double-stranded DNA fragments into two single-stranded DNA fragments
(denaturation). Then, an oligonucleotide primer (also known as a sequencing primer) binds to the single-stranded DNA based
on complementarity between the primer and the DNA sequence.
2. Extension
Next, a mixture of dNTPs and ddNTPs is added by DNA polymerase. If a dNTP is added, extension continues. If a
chain-terminating nucleotide (ddNTPs) is added, extension stops.
