To know the pattern of inheritence - Pedigree Analysis

• A record of inheritance of certain traits for two or more generations is called a Pedigree. 

• A chart that represents the affected members of genetic disorder as well as normal members of a family in the form of a family tree is called a pedigree chart. 

• The study of such a chart to detect genetic trait or genetic diseases in a family is called pedigree analysis. The diagram gives some common symbols in pedigree analysis.

• The analysis of inheritance of trait in several generation of family by tree diagram called Pedigree analysis.

• A series of symbols are used to represent different aspects of a pedigree and to draw a pedigree chart . These principal symbols are as - 

Application of Pedigree analysis.

• In human genetics. Scientists have  developed another approach, called pedigree analysis, to study the inheritance of genes in humans.

• Pedigree analysis is also useful to study the  progeny data  of any population from several generations. Pedigree analysis is also useful when studying species with a long generation time.

• Pedigree  analysis is used to determine whether the trait is Dominant or recessive or sex linked.

• Pedigree analysis is used to trace the inheritance of Mendelian disorder.

For the those dominant traits -

• The affected individuals have at least one affected parent and the phenotype expression generally appears every generation. But two normal parents only have normal offspring.

For the those recessive traits-

• The normal parents can have affected offspring. The affected progeny may be  both male and female.

• Pedigree analysis is the study of a particular trait that is inherited from one generation to another.

• It helps to know the pattern of  inheritance for a particular trait. it can be used to predict the characteristics of the future generations of a particular species, like colour, stature, height, etc.

Polygenic inheritance

• The trait that is controlled by the two or more gene called polygenic traits and inheritance is called polygenic inheritance.

• Such traits are also affected by the environment.

• Human skin color is an example polygenic inheritance or polygenic traits.

• In such inheritance, Each allele put effect on phenotype and such allele is additive.

• Gene A, B and C gene control human skin color. A B and C are dominant dark skin color over ligh skin color with a , and c.

• The genotype with allele AABBCC has dark skin color and genotype aabbcc has ligh skin color. If hybrid recieve allele AaBbCc than it show intermediate skin color.