Types of Chromosome Mutations Aneuploidy 2 n m

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Types of Chromosome Mutations

Types of Chromosome Mutations

Aneuploidy (2 n +/- m) Aneuploids differ from wild-type individuals by part of a

Aneuploidy (2 n +/- m) Aneuploids differ from wild-type individuals by part of a chromosome set. Nondisjunction is a common mechanism for aneuploidy. Aneuploidy can be the cause of disorders such as Down Syndrome.

Examples of Aneuploidy Nullisomy (2 n -2) Usually lethal in diploids Tolerated in some

Examples of Aneuploidy Nullisomy (2 n -2) Usually lethal in diploids Tolerated in some polyploids Monosomy (2 n - 1) Gene imbalance results (missing chromosome) Expression of genes on lone chromosome (hemizygosity) Trisomy (2 n + 1) Gene imbalance results (extra chromosome) Viability depends on chromosome and species Disomy (n + 1) Phenomenon in haploid organisms

Meiotic Nondisjunction Generates Aneuploid Products

Meiotic Nondisjunction Generates Aneuploid Products

Turner Syndrome XO Klinefelter Syndrome XXY

Turner Syndrome XO Klinefelter Syndrome XXY

Meiotic Products of a Trisomic

Meiotic Products of a Trisomic

Characteritstics of Down Syndrome (Trisomy 21)

Characteritstics of Down Syndrome (Trisomy 21)

The Maternal-Age Effect in Down Syndrome

The Maternal-Age Effect in Down Syndrome

Trisomy 13: Patau Syndrome Rarely do fetuses go to term. Rarely do babies survive.

Trisomy 13: Patau Syndrome Rarely do fetuses go to term. Rarely do babies survive. Symptoms include: * cleft palate * atrial septal defect * inguinal hernia Polydactyly is common.

Trisomy 13: Patau Syndrome Severity of symptoms is variable. 7 -year old survivor (deaf

Trisomy 13: Patau Syndrome Severity of symptoms is variable. 7 -year old survivor (deaf and legally blind). Others are not as fortunate. CYCLOPIA

Trisomy 18: Edward’s Syndrome Rarely do fetuses go to term. Rarely do babies survive.

Trisomy 18: Edward’s Syndrome Rarely do fetuses go to term. Rarely do babies survive. Symptoms include: * cleft palate * small face * short sternum * low-set ears * overlapping fingers * clenched fist * clubfeet

Trisomy 18: Edward’s Syndrome These two girls are rare survivors.

Trisomy 18: Edward’s Syndrome These two girls are rare survivors.

Heterochromatin Features of Constitutive Heterochromatin 1. Present at homologous sites on pairs of chromosomes

Heterochromatin Features of Constitutive Heterochromatin 1. Present at homologous sites on pairs of chromosomes 2. Always genetically inert 3. DNA sequences that are not organized into genes 4. Telomeric and centromeric regions Features of Facultative Heterochromatin 1. Referred to as silent chromatin 2. Potential to become heterochromatic (Barr body) 3. Genetic information that is not expressed once chromatin becomes condensed

Mammalian X Chromosome Inactivation Calico cats are usually females heterozygous for orange allele and

Mammalian X Chromosome Inactivation Calico cats are usually females heterozygous for orange allele and black allele at an X-linked locus. Male calico cats are very rare. Why is the case?

X Chromosome Inactivation Most genes on the inactivated X chromosome are silenced (turned off,

X Chromosome Inactivation Most genes on the inactivated X chromosome are silenced (turned off, not expressed). Genes on the inactivated X chromosome remain silenced in descendant cells. Heritable alteration of this type is an example of epigenetic inheritance. Chromosomal DNA sequence remains unchanged.

Mammalian X Chromosome Inactivation Inactivated X chromosome becomes highly condensed, darkly staining structure called

Mammalian X Chromosome Inactivation Inactivated X chromosome becomes highly condensed, darkly staining structure called Barr body. State of inactivation is transmitted down the cell lineage.

Types of Chromosome Mutations Chromosome Mutations Deletion DeficiencyTypes of Chromosome Mutations Chromosome Mutations Deletion Deficiency
Types of Chromosome Mutations Chromosome Mutations Deletion DeficiencyTypes of Chromosome Mutations Chromosome Mutations Deletion Deficiency
Types of Chromosome Mutations Chromosome Mutations Changes inTypes of Chromosome Mutations Chromosome Mutations Changes in
Types of Chromosome Mutations Chromosome Mutations Deletion DeficiencyTypes of Chromosome Mutations Chromosome Mutations Deletion Deficiency
Mutations Mutations Types of Mutations Point Mutations occursMutations Mutations Types of Mutations Point Mutations occurs
Chromosome Structure and Mutations Genetics Chromosome Mutations IncludeChromosome Structure and Mutations Genetics Chromosome Mutations Include
MUTATION SPONTANEOUS MUTATIONS INDUCED MUTATIONS MUTATIONS Mutations areMUTATION SPONTANEOUS MUTATIONS INDUCED MUTATIONS MUTATIONS Mutations are
Mutations Mutations overview Smallscale mutations Missense mutations NonsenseMutations Mutations overview Smallscale mutations Missense mutations Nonsense
Types of Chromosome Mutations Mammalian X Chromosome InactivationTypes of Chromosome Mutations Mammalian X Chromosome Inactivation
Mutations and Genetic Engineering Mutations Types of mutationsMutations and Genetic Engineering Mutations Types of mutations
Types of mutations Point mutations Conditional mutations PointTypes of mutations Point mutations Conditional mutations Point
Mutations Types of Mutations n MUTATIONS are nMutations Types of Mutations n MUTATIONS are n
Chromosome Oragnisation What chromosome is made of chromosomeChromosome Oragnisation What chromosome is made of chromosome
Chromosome and its Structure Chromosome Chromosome means chromaChromosome and its Structure Chromosome Chromosome means chroma
1 Aneuploidy changes in parts of chromosome sets1 Aneuploidy changes in parts of chromosome sets
Genetics disorders2 Numerical changes in chromosome numbers AneuploidyGenetics disorders2 Numerical changes in chromosome numbers Aneuploidy