More than 100.
Developmental abnormalities.
Parts of chromosomes move to other nonhomologous chromosomes or to other regions of the same chromosome.
It can move the allele to a region with inactive chromatin, preventing its expression and resulting in red and white spotted eyes.
Because the chromosome is noticeably shortened.
The resulting recombinant gametes are not viable, so no recombinant progeny are observed.
One large metacentric chromosome and one very small chromosome with two very short arms.
Crosslike structures.
Inversions may have contributed to differences between human and chimpanzee chromosomes.
Two-strand double crossovers.
Variations in the number of copies of particular DNA sequences in the human genome.
The loss of a chromosome segment.
The homologous sequences can align and pair only if the chromosomes form an inversion loop.
Red.
A type of inversion that involves the centromere and alters the DNA sequence without losing or gaining genetic material.
Big E and big F.
A large metacentric chromosome and a fragment that often fails to segregate and is lost.
Cri-du-chat syndrome.
Chromosomal regions susceptible to breakage under certain conditions.
Unequal crossing over.
The normal chromosome must loop out to allow homologous regions to align.
Chromosome mutations that change the structure of individual chromosomes.
One chromosome forms a bump while the other rises upwards, turns down, and lies parallel.
1. Alternate segregation 2. Adjacent-1 segregation 3. Adjacent-2 segregation.
Deletions.
The movement of genetic material between nonhomologous chromosomes or within the same chromosome.
Cleft lip and palate, severe intellectual disability, deletion on chromosome 4 (long arm).
The individual has one normal chromosome and one chromosome with the duplication.
The human X chromosome.
By causing genes to move to new locations or by breaking genes and disrupting their function.
Genes big C, big D, and big E.
The results of single crossovers within inversions.
They exhibit reduced recombination among genes located in the inverted region.
A single copy of the gene is not sufficient to produce a wild-type phenotype.
One is wild type (normal) and the other has an inversion.
By examining chromosomes with a microscope.
It allows the homologous sequences of the chromosomes to align.
An inversion may break a gene into two parts, potentially destroying its function.
Changes in overall size, alteration of banding patterns, and behavior in meiosis.
Big C, big D, and big E.
An inversion loop.
T₂ (blue) and N₂ (blue) with genes M, N, O, P, Q, R, S, T.
It results in a reduced number of facets in the eye, making the eye smaller and bar-shaped instead of oval.
The chromosomes form an inversion loop.
No special problems arise, and the homologous chromosomes can pair and separate normally.
The unequal number of gene copies resulting from duplications and deletions.
A, B, C, D, E, F, and G.
Duplications where the two copies are found on different chromosomes.
Normal wing venation has a round outer edge, while Notch mutation shows notches at the edges and tips.
The original chromosome is restored, and no rearrangement occurs.
Two homologous chromosomes with genes A, B, C, D, E, F, and G on the top chromosome, and A, B, C, D, and G on the bottom chromosome.
Because they have too many copies of some genes and no copies of others.
The Bar phenotype.
Williams–Beuren syndrome.
Problems in chromosome pairing due to non-homologous chromosomes.
The homologous chromosomes form an inversion loop.
An overall reduction in chromosome number.
A rearrangement where a chromosome segment is inverted—turned 180 degrees.
Red–green color blindness.
It generates the mutated chromosome AB•CDG.
Homologous sequences align.
Phenotypic effects may arise even when breaks lie between genes.
Big A, big B, big C, big D, big E, big F, and big G.
Genes big C, big D, and big E.
A series of X-linked wing mutations often resulting from chromosome deletions.
Because some genes are present in two copies.
Robertsonian translocation.
The normal chromosome loops out.
It depends on the nature of the translocation.
A mutation that doubles part of a chromosome.
There is a two-way exchange of segments between nonhomologous chromosomes.
Variations that include duplications and deletions of DNA sequences.
Segments of two other chromosomes.
A dicentric bridge.
They have greatly reduced numbers of facets in their eyes.
Distinctive mouth shape, small hands, small head, and intellectual disability.
A segment of the chromosome is deleted, leaving fewer genes.
The number of facets is extremely reduced.
It refers to the alteration in gene expression due to changes in gene position caused by inversions.
Chromosomes do not align properly, leading to duplications and deletions.
Expression of a normally recessive mutation indicating a deletion on one of the homologous chromosomes.
A cross-like configuration forms due to homologous sections of chromosomes.
Recombination is reduced, leading to recombinant chromosomes with too many copies of some genes and no copies of others.
They are quite common, with each person possibly having as many as a thousand copy-number variations.
It results in 4 viable gametes: N₁, N₂; N₁, N₂; T₁, T₂; and T₁, T₂.
A single crossover within the inversion leads to abnormal gametes.
They arose from an original primordial globin gene that underwent a series of duplications.
No, inversions do not result in the loss or gain of genetic material; they only alter the DNA sequence.
The chromosomes separate, resulting in gametes with different gene combinations.
Inversions can have pronounced phenotypic effects despite not changing the amount of genetic material.
Feeding difficulty at early age, obesity after one year, mild to moderate intellectual disability, deletion on chromosome 18 (short arm).
N and N for normal chromosomes 1 and 2.
They have relatively thinner bar eyes.
It is usually lost when the nucleus re-forms because spindle microtubules do not attach to it.
Duplications, deletions, inversions, and translocations.
No recombinant progeny result because the gametes are missing some genes.
Rapid genome sequencing techniques.
Expanding nucleotide repeats, specifically an increase in CGG trinucleotide repeats.
Developmental problems.
Approximately half of the gametes are produced by alternate or adjacent-1 segregation.
More than 100,000 bp in length.
Enzymes may stall while unwinding the DNA, leading to unwound stretches that are vulnerable to breakage.
An unusual structure results with abnormal chromatids.
Sites that develop constrictions or gaps when cells are grown in culture and are prone to breakage under certain conditions.
The duplicated region loops out during pairing.
A structure similar to that seen in individuals heterozygous for duplications.
Duplications, deletions, inversions, and translocations.
Neurofibromatosis.
A blue part with genes Q, R, S, and T.
Some function during adult stages, while others function during embryonic and fetal development.
A type of translocation where the long arms of two acrocentric chromosomes join at a common centromere, forming a metacentric chromosome.
Osteoporosis, autism, schizophrenia, and others.
They have normal-sized eyes.
It encodes a receptor that transmits signals from outside the cell to its interior, important for fly development.
They have smaller, bar-shaped eyes.
A fragile site on the human X chromosome.
The chromosome will not segregate in meiosis or mitosis and will usually be lost.
Williams–Beuren syndrome.
They provide extra copies of genes that can mutate while the original copy maintains essential functions.
They do not pair in meiosis.
It has spots rather than stripes.
Gametes that possess one complete set of chromosome segments, which are functional and can produce viable progeny.
A process where segments of two chromosomes are exchanged, such as between chromosomes AB•CDEFG and MN•OPQRS.
They are 98% identical.
Big A, big B, big C, big D, and big G.
Abnormal gametes that do not give rise to viable offspring.
One chromosome has 1 red opsin gene and 2 green opsin genes (duplication), while the other chromosome is missing the green opsin gene (deletion).
A single crossover leads to abnormal gametes.
The Notch phenotype.
They reveal that several human chromosomes differ from those of chimpanzees by pericentric inversions.
An inversion loop.
They are shorter and do not contain all the genes present in the original.
They behave in a dominant manner, causing notched wings when heterozygous.
A mutation in which a part of a chromosome is lost.
Translocation involves movement between nonhomologous chromosomes, while crossing over involves exchange between homologous chromosomes.
Small head, widely spaced eyes, round face, and intellectual disability.
Alternate segregation, adjacent-1 segregation, and adjacent-2 segregation.
The expression of recessive genes on the homologous chromosome due to a deletion.
N and N move toward one pole, and T and T move toward the opposite pole.
Seizures, severe intellectual disability, and delayed growth.
The loss of all copies of the Notch gene prevents normal development.
Inversions that do not include the centromere.
The short arm of one chromosome is exchanged with the long arm of another.
A segment of the chromosome is duplicated, resulting in an additional set of genes.
Double Bar.
It can lead to problems in developmental processes that depend on the interaction of many proteins.
On the X chromosome.
Cri-du-chat syndrome.
Intrachromosomal duplications, where the two copies are found on the same chromosome.
An inversion loop.
It is reduced within an inversion.
c. Paracentric inversion.
No dicentric bridges or acentric fragments are produced.
The individual carries the duplication on both homologous chromosomes.
16% (11 out of 67 children).
Two resulting chromatids have too many copies of some genes and no copies of others.
They separate and move toward opposite poles.
At least 5 million base pairs.
A translocation where genetic material moves from one chromosome to another without reciprocal exchange.
They form an unusual structure and can result in fused chromosomes.
A dicentric bridge.
It loops out when homologous chromosomes pair in prophase I.
AB•CDG and MN•OPEFQRS.
From thousands of base pairs to several million base pairs.
They produce extra copies of some genes, altering the relative amounts of interacting products.
Because the two homologous chromosomes usually separate in meiosis.
Genes big C, big D, and big E.
A duplication where the duplicated segment is located some distance from the original segment, either on the same chromosome or a different one.
It refers to changes in gene expression due to a gene being moved to a new location under different regulatory control.
Neurofibromatosis.
They have two copies of some genes and no copies of others.
Double-stranded breaks in the DNA molecule.
By suppressing recombination among a set of genes.
It leads to unbalanced gametes and no recombinant progeny.
Errors in crossing over or crossing over between repeated DNA sequences.
They die early in embryonic development.
It is often lost due to insufficient mass to segregate properly during mitosis and meiosis.
Many probably have no observable phenotypic effects.
One normal non-recombinant gamete, two non-viable recombinant gametes, and one non-recombinant gamete with pericentric inversion.
Nonviable gametes are usually produced.
Duplications allow for the evolution of new genes by providing extra copies that can mutate and assume new functions.
X-linked inheritance.
Crosslike configurations consisting of all four chromosomes.
It is lost.
The chromosome must break in two places.
Small head and mild to moderate intellectual disability.
A duplication where the duplicated segment is inverted compared to the original sequence.
If a break occurs within a gene, it can lead to the disruption of that gene's function.
It helped identify the precise location of the gene associated with neurofibromatosis.
The duplicated region (big E and big F) must loop out.
The normal chromosome must loop out to align homologous sequences, causing genes E and F to loop out from the top chromosome.
The centromeres are pulled toward opposite poles, separating the homologous chromosomes.
Wolf–Hirschhorn syndrome.
They align with the red chromosome N₁ to form a bookend shape during meiosis.
As an incompletely dominant, X-linked trait.
Because genes are either missing or present in too many copies.
It leads to imbalances in the amounts of gene products due to abnormal gene dosage.
They have the thinnest and shortest bar eyes.
Inversions that include the centromere.
Imbalances in gene product amounts, expression of normally recessive mutations, and loss of wild-type allele masking.
Chromosome rearrangements and copy-number variations collectively.
Many plants, some species of Drosophila, and mosquitoes.
It regulates the translation of other proteins and plays a role in the development of neural synapses.
Duplicated sequences in the human genome that are greater than a thousand base pairs in length.
Genes big E, big F, and big G switch with big Q, big R, and big S.
A chromatid that lacks a centromere.
A segment of a chromosome is turned 180 degrees.
About 4%.
The interaction of many genes.
The Human Genome Project.
One or both chromosomes must loop and twist to line up homologous regions.
One chromatid may have two centromeres, while another may lack a centromere.
Some cases of Down syndrome.
Because developmental processes depend on the relative amounts of proteins encoded by different genes.
The gene sequences themselves are not altered, and no genetic information is missing.
Unequal crossing over.
The chromosome is more likely to break.
A duplication where the duplicated segment is immediately adjacent to the original segment.
Duplications can have severe consequences when the precise balance of gene products is critical to cell function.
Genes big E and big F.
Genes big D, big E, and big F.
They contain original, nonrecombinant gene sequences.
The specific genes located in the deleted region.
By the relative amounts of gene products.
N and T move toward one pole, and T and N move toward the other pole.
Stripes running horizontally over the body.
Because some chromosome segments are present in two copies, while others are missing.
Distinctive facial features, heart defects, high blood pressure, and cognitive impairments.
The amount of a particular protein synthesized is often directly related to the number of copies of its corresponding gene.
Red–green color blindness.
The gene that encodes fragile X mental retardation protein (FMRP).
A segment of a chromosome moves to a non-homologous chromosome or another place on the same chromosome.
Delayed development, asymmetry of the head, fuzzy scalp, small nose, low-set ears.
An autosomal dominant mutation.
By the appearance of a characteristic loop structure.
They have somewhat smaller eyes with a reduced number of facets.
Because all copies of any essential genes located in the deleted region are missing.
About 1 in 5000 male births.
A mutation in which part of the chromosome has been doubled.
The original copy maintains essential functions while the extra copy is free to undergo mutations.
A segment of the chromosome is turned 180 degrees, reversing the order of genes.
By physically linking genes that were formerly on different chromosomes, potentially altering their regulatory sequences.
Late in S phase.
By identifying patients with a translocation affecting chromosome 17.
Small head, short neck, low hairline, reduced growth, intellectual disability.
Two paired X chromosomes do not align properly.
No, it is not completely understood despite recent advances.
A chromatid that has two centromeres.
