Variation in Chromosome Structure and Number

These flashcards cover key concepts regarding chromosome structure and number from the lecture.

What is genetic variation?

Differences between members of the same species or those of different species.

What are the types of chromosomal alterations?

Deletions, duplications, inversions, and translocations.

What is a karyotype?

A way to detect chromosomal abnormalities through micrographs of metaphase chromosomes.

What type of chromosomal deletion involves the loss of a terminal fragment?

Terminal deletion.

What is Cri-du-chat syndrome?

A condition caused by a deletion of part of chromosome 5, leading to mental deficiencies and facial anomalies.

What is Williams syndrome characterized by?

Heart defects, unusual facial features, and failure to gain weight appropriately in infancy.

How do repetitive sequences affect chromosomes?

They can cause misalignment between homologous chromosomes during recombination.

What is an inversion in chromosome structure?

A segment of a chromosome that has been flipped to the opposite orientation.

What is a Robertsonian translocation?

A chromosomal rearrangement that involves breaks near the centromeres of two non-homologous acrocentric chromosomes.

What are the consequences of crossing over in the inversion loop?

It can lead to the production of highly abnormal chromosomes.

What is euploidy?

Variation in the number of complete sets of chromosomes.

What does aneuploidy refer to?

Variation in the number of particular chromosomes within a set.

What is haploinsufficiency?

The requirement for two wild-type copies of a gene for a normal phenotype.

What is segregation in genetics?

Segregation is the process by which alleles of a gene separate from each other during gamete formation.

Define Mendel's Law of Segregation.

Mendel's Law of Segregation states that during the formation of gametes, the two alleles for a trait segregate from each other, ensuring that each gamete carries only one allele for each gene.

How does segregation relate to meiosis?

Segregation occurs during meiosis, specifically in anaphase I, where homologous chromosomes are pulled apart, leading to the separation of alleles.

Fill in the blank: During segregation, each gamete receives __ allele(s) for each gene.

one

What is pericentric inversion?

Pericentric inversion is a type of chromosomal inversion that includes the centromere in the inverted region, resulting in a chromosome with altered genes on either side of the centromere.

What is paracentric inversion?

Paracentric inversion is a type of chromosomal inversion that does not include the centromere in the inverted region, affecting only one arm of

Fill in the blank: Alternate segregation occurs during meiosis, where _ homologous chromosomes are separated into different gametes.

Alternate segregation occurs during meiosis, where non-homologous chromosomes are separated into different gametes.

What is alternate segregation in genetics?

Alternate segregation is a process during meiosis where alternate chromosomes are segregated into different gametes.

What is the result of alternate segregation?

The result of alternate segregation is the formation of viable gametes that may lead to healthy offspring.

How does alternate segregation differ from adjacent segregation?

In adjacent segregation, adjacent non-homologous chromosomes are segregated together, often resulting in inviable gametes.

What is the significance of alternate segregation in meiosis?

Alternate segregation is significant because it helps maintain genetic diversity by ensuring that certain combinations of alleles are preserved.

In which phase of meiosis does alternate segregation occur?

Alternate segregation occurs during anaphase I of meiosis.

What type of chromosomes are involved in alternate segregation?

Alternate segregation involves homologous chromosomes that can have different alleles.

What genetic disorders can result from improper segregation?

Improper segregation can lead to genetic disorders such as Down syndrome due to aneuploidy.

How does alternate segregation affect genetic recombination?

Alternate segregation promotes genetic recombination by allowing for the exchange of genetic material between homologous chromosomes.

Can alternate segregation happen in mitosis?

No, alternate segregation is specific to meiosis; mitosis does not involve the segregation of homologous chromosomes.

What is the role of crossing over in relation to alternate segregation?

Crossing over enhances the effects of alternate segregation by creating new allele combinations before the separation of homologous chromosomes.