MID- CR Chromosomal Rearrangement

Chromosomal rearrangements

Changes to the arrangement of genetic material within a chromosome.

Balanced rearrangement

A type of chromosomal rearrangement where there is no net loss or gain of genetic information.

Chromosomal rearrangements

Changes to the arrangement of genetic material within a chromosome.

Balanced rearrangement

A type of chromosomal rearrangement where there is no net loss or gain of genetic information.

Unbalanced rearrangement

A type of chromosomal rearrangement resulting in a loss or gain of chromosomal segments.

Inversion

A chromosomal rearrangement where a segment of a chromosome is reversed end to end.

Paracentric inversion

An inversion that does not include the centromere.

Pericentric inversion

An inversion that includes the centromere.

Translocation

A chromosomal rearrangement involving the transfer of a chromosome segment from one chromosome to another, non-homologous chromosome.

Philadelphia chromosome

A specific translocation between chromosomes 9 and 22 associated with chronic myeloid leukemia.

Deletion

The loss of a segment of a chromosome.

Duplication

The presence of an extra copy of a chromosomal segment.

Errors in DNA damage repair

Common causes of chromosomal rearrangements.

Example of unbalanced chromosomal rearrangement

Deletion.

Formation of a ring chromosome

Occurs when a chromosome breaks in two places and the ends fuse together.

Parts of Philadelphia chromosome

Result of a translocation between chromosomes 9 and 22.

Cause of Cri-du-chat syndrome

A deletion on chromosome 5.

Balanced rearrangements in a parent

Can lead to unbalanced gametes and potential genetic disorders in offspring.

Inversions suppress recombination

Can lead to reproductive isolation and speciation.

Involves acrocentric chromosomes

Robertsonian translocation.

Altered gene expression and disease

Can result from chromosomal rearrangements that disrupt essential genes.

Importance of understanding chromosomal rearrangements

Crucial in fields such as clinical genetics, fertility, and cancer research.

Structural chromosomal rearrangements

Alters chromosome structure.

Balanced rearrangements

Involve a rearrangement of chromosomal material without any net loss or gain.

Deletion in unbalanced rearrangements

Results in a loss of chromosomal segments.

Inversion process

Occurs when a segment of a chromosome rotates 180 degrees before reattachment.

Translocation segment transfer

Involves the transfer of a chromosome segment to a non-homologous chromosome.

Loss of a chromosome segment

Referred to as deletions.

Cri-du-chat chromosome

Caused by a deletion on chromosome 5.

Formation of ring chromosomes

Occurs when a chromosome breaks in two places and the ends fuse.

Impact on fertility

Chromosomal rearrangements can affect fertility, especially in germ cells.

Chromosomal repair errors

Common causes of chromosomal rearrangements.

Balanced reciprocal translocations

Typically do not cause phenotypic abnormalities in carriers.

Crossing over impact

Inversions can lead to increased production of abnormal chromatids.

Acentric fragments during meiosis

Lack a centromere and are often lost.

Dicentric chromosomes

Form when crossing over occurs in inversions.

Consequences of unbalanced gametes

Can lead to miscarriages or developmental issues.

Role in evolution

Inversions can contribute to speciation.

Difference in balanced and unbalanced rearrangements

Balanced involves no loss/gain of genetic info; unbalanced involves loss/gain.

Phenotypic impact of unbalanced rearrangements

Often leads to severe developmental abnormalities.

Inversions and fertility

Can lead to reduced fertility in heterozygous individuals.

Chromosomal regions and inversions

Breakpoints often occur in regions of repetitive nucleotides.

Significance in genetic counseling

Understanding chromosomal rearrangements helps in diagnosis and treatment.

Ectopic recombination

Process where repetitive nucleotide regions may be reused in inversions.

Crossing-over within inversion loops

Can result in unbalanced gametes.

Evidence of natural selection

Inversions can preserve favorable gene combinations.

Genetic disorders associated with inversions

Can lead to conditions like Down syndrome and Cri-du-chat syndrome.

Molecular mechanisms of inversions

Involve two chromosomal breaks and reattachment.

Acentric fragment during meiosis

Is lost due to lack of centromere.

Phenotypic outcomes of chromosomal disorders

Can range from mild to severe based on the type of rearrangement.

Mechanisms underlying chromosomal integrity

Critical for understanding fertility issues.

Association of inversions with disease

Can disrupt essential genes and alter gene dosage.

Significance of chromosomal research

Vital for advancements in clinical genetics and cancer research.