40 Questions
What type of translocation involves the exchange of genetic material between two non-homologous chromosomes?
Reciprocal translocation
What is the result of a Robertsonian translocation?
A fusion of the long arms of two acrocentric chromosomes
What is the karyotype of a normal carrier with a Robertsonian translocation?
45,XX,-14,-21,+t(14q21q)
Which type of translocation is always unbalanced?
Deletion
What is the consequence of a Robertsonian translocation in a normal carrier?
The carrier is unaffected but may produce offspring with a genetic disorder
What is the difference between a reciprocal translocation and a Robertsonian translocation?
Reciprocal translocation involves the exchange of genetic material, while Robertsonian translocation involves the fusion of long arms
Which type of translocation can be balanced or unbalanced?
All of the above
What is the result of a balanced reciprocal translocation?
No loss or gain of genetic material
What is the karyotype of a carrier with a Robertsonian translocation that produces a child with Down syndrome?
46,XY,-14,+rob(14q21q)
Which type of structural abnormality is always unbalanced?
All of the above
What is the characteristic of reciprocal translocation?
It involves the exchange of genetic material between two non-homologous chromosomes
What is the outcome of a Robertsonian translocation?
A reduction in chromosome number
What is the characteristic of a balanced translocation?
It does not result in a loss or gain of genetic material
What is the consequence of a Robertsonian translocation in a normal carrier?
The carrier is always normal
What is the difference between a reciprocal translocation and a Robertsonian translocation?
One involves the exchange of genetic material, while the other involves the fusion of genetic material
Which type of structural abnormality may be balanced or unbalanced?
Inversions
What is the karyotype of a carrier with a Robertsonian translocation that produces a child with Down syndrome?
45,XY,-14,+rob(14q21q)
What is the characteristic of a Robertsonian translocation?
It involves the fusion of genetic material between two acrocentric chromosomes
What is the outcome of a reciprocal translocation?
No loss or gain of genetic material
Which type of structural abnormality is always unbalanced?
Deletions
What is the main difference between reciprocal translocation and Robertsonian translocation?
The location of the break in the chromosomes
What is the consequence of a balanced reciprocal translocation?
No net loss or gain of genetic material
What is the characteristic of a Robertsonian translocation carrier?
Has a normal phenotype
What is the outcome of a Robertsonian translocation in a normal carrier?
May produce a child with Down syndrome
Which type of structural abnormality is characterized by the fusion of two acrocentric chromosomes?
Robertsonian translocation
What is the consequence of a deletion?
Loss of genetic material
What is the characteristic of an unbalanced translocation?
Loss or gain of genetic material
What is the result of a reciprocal translocation between two chromosomes?
Two derivative chromosomes with no net loss or gain of genetic material
What is the characteristic of an isochromosome?
Is always unbalanced
What is the consequence of an inversion?
No net loss or gain of genetic material
What is the key feature of reciprocal translocation?
Exchange of genetic material between two non-homologous chromosomes
Which type of translocation is always functionally balanced?
Robertsonian translocation
What is the outcome of a Robertsonian translocation in a normal carrier?
No loss of genetic material, but a reduction in chromosome number
Which type of translocation may be unbalanced?
All of the above
What is the characteristic of an isochromosome?
A chromosome with two identical arms
Which type of structural abnormality is characterized by a break at or near the centromere?
Robertsonian translocation
What is the karyotype of a carrier with a Robertsonian translocation that produces a child with Down syndrome?
45,XX,-14,-21,+t(14q21q)
Which type of translocation involves the fusion of two acrocentric chromosomes?
Robertsonian translocation
What is the consequence of a deletion?
Loss of important genetic material
Which type of structural abnormality may result in the production of a child with Down syndrome?
Robertsonian translocation
Study Notes
Translocation
- Involves exchange of genetic material between two chromosomes, with two types: Reciprocal translocation and Robertsonian translocation (centric fusion)
Reciprocal Translocation
- No loss of genetic material, but an exchange of genetic material between two non-homologous chromosomes to form two derivative chromosomes
- Example: balanced reciprocal translocation between a chromosome 3 and a chromosome 17, with a G-banding karyotype of 46, XX, t (3q;17q)
Robertsonian Translocation (Centric Fusion)
- Results from break at or near the centromere in two acrocentric chromosomes (D/D, D/G, G/G) and subsequent fusion of their long arms
- The fragment formed by fusion of their short arms is lost
- Functionally balanced translocation, although chromosome number is reduced to 45
- Carriers are normal because the two short arms that are lost do not carry important genetic material
- Example: Normal carrier with a G-banding karyotype of 45,XX,-14,-21,+t(14q21q)
Production of Down Syndrome
- A normal carrier of Robertsonian translocation can produce Down syndrome
- Example: G-banding karyotype of 46,XY,-14,+rob(14q21q) (Down Syndrome)
Types of Structural Abnormalities
- Deletions, ring chromosomes, and isochromosomes are always unbalanced
- Inversions, insertion, reciprocal translocations, and Robertsonian translocations may be balanced or unbalanced
Karyotype Nomenclature
- Normal female or male: 46, XX or 46,XY
- Plus (+) or minus (-) sign followed by a number indicates an extra or missing entire chromosome: e.g. 47,XX,+21 or 45, XX, -15
- When a piece of a chromosome is missing, the chromosome number is indicated followed by a 'p' or 'q' and a minus (-) sign: e.g. 5p-
- Other notations include 'del' (deletion), 'dup' (duplication), 'inv' (inversion), 'ins' (insertion), 's' (satellite), 'rob' (Robertsonian translocation), and 't' (translocation)
Translocation
- Involves exchange of genetic material between two chromosomes, with two types: Reciprocal translocation and Robertsonian translocation (centric fusion)
Reciprocal Translocation
- No loss of genetic material, but an exchange of genetic material between two non-homologous chromosomes to form two derivative chromosomes
- Example: balanced reciprocal translocation between a chromosome 3 and a chromosome 17, with a G-banding karyotype of 46, XX, t (3q;17q)
Robertsonian Translocation (Centric Fusion)
- Results from break at or near the centromere in two acrocentric chromosomes (D/D, D/G, G/G) and subsequent fusion of their long arms
- The fragment formed by fusion of their short arms is lost
- Functionally balanced translocation, although chromosome number is reduced to 45
- Carriers are normal because the two short arms that are lost do not carry important genetic material
- Example: Normal carrier with a G-banding karyotype of 45,XX,-14,-21,+t(14q21q)
Production of Down Syndrome
- A normal carrier of Robertsonian translocation can produce Down syndrome
- Example: G-banding karyotype of 46,XY,-14,+rob(14q21q) (Down Syndrome)
Types of Structural Abnormalities
- Deletions, ring chromosomes, and isochromosomes are always unbalanced
- Inversions, insertion, reciprocal translocations, and Robertsonian translocations may be balanced or unbalanced
Karyotype Nomenclature
- Normal female or male: 46, XX or 46,XY
- Plus (+) or minus (-) sign followed by a number indicates an extra or missing entire chromosome: e.g. 47,XX,+21 or 45, XX, -15
- When a piece of a chromosome is missing, the chromosome number is indicated followed by a 'p' or 'q' and a minus (-) sign: e.g. 5p-
- Other notations include 'del' (deletion), 'dup' (duplication), 'inv' (inversion), 'ins' (insertion), 's' (satellite), 'rob' (Robertsonian translocation), and 't' (translocation)
Translocation
- Involves exchange of genetic material between two chromosomes, with two types: Reciprocal translocation and Robertsonian translocation (centric fusion)
Reciprocal Translocation
- No loss of genetic material, but an exchange of genetic material between two non-homologous chromosomes to form two derivative chromosomes
- Example: balanced reciprocal translocation between a chromosome 3 and a chromosome 17, with a G-banding karyotype of 46, XX, t (3q;17q)
Robertsonian Translocation (Centric Fusion)
- Results from break at or near the centromere in two acrocentric chromosomes (D/D, D/G, G/G) and subsequent fusion of their long arms
- The fragment formed by fusion of their short arms is lost
- Functionally balanced translocation, although chromosome number is reduced to 45
- Carriers are normal because the two short arms that are lost do not carry important genetic material
- Example: Normal carrier with a G-banding karyotype of 45,XX,-14,-21,+t(14q21q)
Production of Down Syndrome
- A normal carrier of Robertsonian translocation can produce Down syndrome
- Example: G-banding karyotype of 46,XY,-14,+rob(14q21q) (Down Syndrome)
Types of Structural Abnormalities
- Deletions, ring chromosomes, and isochromosomes are always unbalanced
- Inversions, insertion, reciprocal translocations, and Robertsonian translocations may be balanced or unbalanced
Karyotype Nomenclature
- Normal female or male: 46, XX or 46,XY
- Plus (+) or minus (-) sign followed by a number indicates an extra or missing entire chromosome: e.g. 47,XX,+21 or 45, XX, -15
- When a piece of a chromosome is missing, the chromosome number is indicated followed by a 'p' or 'q' and a minus (-) sign: e.g. 5p-
- Other notations include 'del' (deletion), 'dup' (duplication), 'inv' (inversion), 'ins' (insertion), 's' (satellite), 'rob' (Robertsonian translocation), and 't' (translocation)
Translocation
- Involves exchange of genetic material between two chromosomes, with two types: Reciprocal translocation and Robertsonian translocation (centric fusion)
Reciprocal Translocation
- No loss of genetic material, but an exchange of genetic material between two non-homologous chromosomes to form two derivative chromosomes
- Example: balanced reciprocal translocation between a chromosome 3 and a chromosome 17, with a G-banding karyotype of 46, XX, t (3q;17q)
Robertsonian Translocation (Centric Fusion)
- Results from break at or near the centromere in two acrocentric chromosomes (D/D, D/G, G/G) and subsequent fusion of their long arms
- The fragment formed by fusion of their short arms is lost
- Functionally balanced translocation, although chromosome number is reduced to 45
- Carriers are normal because the two short arms that are lost do not carry important genetic material
- Example: Normal carrier with a G-banding karyotype of 45,XX,-14,-21,+t(14q21q)
Production of Down Syndrome
- A normal carrier of Robertsonian translocation can produce Down syndrome
- Example: G-banding karyotype of 46,XY,-14,+rob(14q21q) (Down Syndrome)
Types of Structural Abnormalities
- Deletions, ring chromosomes, and isochromosomes are always unbalanced
- Inversions, insertion, reciprocal translocations, and Robertsonian translocations may be balanced or unbalanced
Karyotype Nomenclature
- Normal female or male: 46, XX or 46,XY
- Plus (+) or minus (-) sign followed by a number indicates an extra or missing entire chromosome: e.g. 47,XX,+21 or 45, XX, -15
- When a piece of a chromosome is missing, the chromosome number is indicated followed by a 'p' or 'q' and a minus (-) sign: e.g. 5p-
- Other notations include 'del' (deletion), 'dup' (duplication), 'inv' (inversion), 'ins' (insertion), 's' (satellite), 'rob' (Robertsonian translocation), and 't' (translocation)
Learn about translocation, a type of chromosomal abnormality, including reciprocal translocation and Robertsonian translocation. Understand how genetic material is exchanged between chromosomes.
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