PATTERNS OF
INHERITANCE
Genetics
◦It is a branch of biology concerned with
the study of genes, genetic variation and
heredity in organism.
Inheritance
◦A process by which genetic information is
passed on from parents to child.
Variation
◦Any difference between cells, individual
organisms or groups of organism of any
species.
Allele
◦Different form of a gene
INCOMPLETE DOMINACE PATTERN OF
INHERITANCE
◦ INCOMPLETE DOMINACE PATTERN OF INHERITANCE
◦ Non-Mendelian Inheritance- any pattern of inheritance in which traits does not
segregate in accordance with Mendel's laws. The two alleles are neither dominant nor
recessive.
◦
◦ Incomplete Dominance occurs when the phenotype of the offspring is somewhere in
between the phenotypes of both parents; a completely dominant allele does not
occur. Neither allele is dominant over the other. This results in a third phenotype in
which the expressed physical trait is a combination of the dominant and recessive
phenotypes.
◦ Genotype- combination of alleles that an individual possesses for a
specific gene
◦ Genotypic ratio- the number of times a genotype would appear in the
offspring after a test cross.
◦ Ex: 1RR: 2Rr:1rr.
◦
◦ Phenotype- organism’s observable characteristics
◦ Phenotypic ratio pertains to the relative number of offspring manifesting
a particular trait or combination of traits. Ex: (3 pink: 1 red)
◦
CODOMINANCE PATTERN OF
INHERITANCE
◦Codominance occurs when both alleles
are expressed equally in the phenotype of
the heterozygote offspring, exhibiting the
traits of both parents.