- AFemale, healthy individual, parents
- BFemale, affected individual, parents
- ✓Male, affected individual, parents
- DMale, affected individual, progeny
Square represents male blackened square or circle represents affected individual.
Horizontal line represents-parents
The study of inheritance of genetic traits in several generations of a human family in the form of a family tree diagram is called pedigree analysis.
Advantages
$(i)$ It helps in genetic counselling to avoid disorders
$(ii)$ It shows the origin of a trait and flow of a trait in a family
$(iii)$ It is important to know the possibility of a recessive allele that can cause genetic disorders like colour blindness, haemophilia, etc.
Signosed in the pedigree are
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$I.$ In the centre of each I-band is an elastic fibre ($Z-$line) which bisects it
$II.$ Thin filament are firmly attached to the $Z-$line
$III.\;M-$line is a fibrous membrane in the middle of $A-$band
$IV.$ A sarcomere comprises one full$-A $ band and two half $I-$bands