Barr bodies can be best defined as inactive X chromosomes in a female somatic cell. This structure is used to verify whether an individual is genetically female or not. This structure can be characterised as condensed chromatin. It is a chromatin-positive substance.

What is called pedigree analysis?

A pedigree is a genetic representation of a family tree that shows the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors from one generation to the next. It shows the relationships between family members and indicates which individual expresses or silently carries the trait in question. In a simpler way, pedigree analysis shows the inheritance of genes in humans. Relationships in a pedigree chart are shown as a series of lines. A horizontal line connects parents, and a vertical line connects their offspring. Squares represent males, and circles represent females. A person with unknown gender is represented by a diamond shape. A person with the phenotype in question is represented by a darker (filled-in) symbol. Heterozygotes are indicated by a shaded dot inside a symbol or a half-filled symbol.

E M B I B E

Zoology Crash Course (Based on Revised Syllabus-2023)>Chapter 4 - Principles of Inheritance and Variation>Exercise>Q 8

MEDIUM

12th Tamil Nadu Board

IMPORTANT

Earn 100

Define dosage compensation?

Important Questions on Principles of Inheritance and Variation

HARD

12th Tamil Nadu Board

IMPORTANT

Zoology Crash Course (Based on Revised Syllabus-2023)>Chapter 4 - Principles of Inheritance and Variation>Exercise>Q 9

What is heterochromatinisation?

MEDIUM

12th Tamil Nadu Board

IMPORTANT

Zoology Crash Course (Based on Revised Syllabus-2023)>Chapter 4 - Principles of Inheritance and Variation>Exercise>Q 10

What is meant by royal jelly?

EASY

12th Tamil Nadu Board

IMPORTANT

Zoology Crash Course (Based on Revised Syllabus-2023)>Chapter 4 - Principles of Inheritance and Variation>Exercise>Q 11

Define Barr body.

EASY

12th Tamil Nadu Board

IMPORTANT

Zoology Crash Course (Based on Revised Syllabus-2023)>Chapter 4 - Principles of Inheritance and Variation>Exercise>Q 12

Is Y-linked inheritance sex-linked?

MEDIUM

12th Tamil Nadu Board

IMPORTANT

Zoology Crash Course (Based on Revised Syllabus-2023)>Chapter 4 - Principles of Inheritance and Variation>Exercise>Q 13

In the following pedigree chart, state if the trait is autosomal dominant, autosomal recessive or sex-linked. Give a reason for your answer.

Question Image

MEDIUM

12th Tamil Nadu Board

IMPORTANT

Zoology Crash Course (Based on Revised Syllabus-2023)>Chapter 4 - Principles of Inheritance and Variation>Exercise>Q 14

What is a pedigree analysis? Suggest how such an analysis can be useful.

HARD

12th Tamil Nadu Board

IMPORTANT

Zoology Crash Course (Based on Revised Syllabus-2023)>Chapter 4 - Principles of Inheritance and Variation>Exercise>Q 15

The pedigree chart given below shows a particular trait which is absent in parents but present in the next generation irrespective of sexes. Draw your conclusion on the basis of the pedigree.

Question Image