MUTATIONS Mutations Changes to DNA are called mutations

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MUTATIONS

MUTATIONS

Mutations Changes to DNA are called mutations change the DNA u changes the m.

Mutations Changes to DNA are called mutations change the DNA u changes the m. RNA u may change protein m. RNA u may change trait u protein trait TACGCACATTTACG AUGCGUGUAAAUGC aa aa

What Causes Mutations? There are two ways in which DNA can become mutated: Mutations

What Causes Mutations? There are two ways in which DNA can become mutated: Mutations Parent can be inherited. to child Mutations can be acquired. Environmental damage Mistakes when DNA is copied

Are Mutations Helpful or Harmful? Mutations happen regularly Almost all mutations are neutral Chemicals

Are Mutations Helpful or Harmful? Mutations happen regularly Almost all mutations are neutral Chemicals & UV radiation cause mutations Many mutations are repaired by enzymes

Are Mutations Helpful or Harmful? Some type of skin cancers and leukemia result from

Are Mutations Helpful or Harmful? Some type of skin cancers and leukemia result from somatic mutations Some mutations may improve an organism’s survival (beneficial)

Types of Chromosomal Mutations

Types of Chromosomal Mutations

Chromosome Mutations May Involve: Changing the structure of a chromosome Changing number the

Chromosome Mutations May Involve: Changing the structure of a chromosome Changing number the

Chromosome Mutations Five types exist: Deletion Inversion Duplication Translocation Nondisjunction

Chromosome Mutations Five types exist: Deletion Inversion Duplication Translocation Nondisjunction

Deletion Due to breakage A piece of a chromosome is lost ABCD-EFGH ABCD-EF

Deletion Due to breakage A piece of a chromosome is lost ABCD-EFGH ABCD-EF

Inversion Chromosome segment breaks off Segment flips around backwards Segment reattaches ABCD-EFGH ABDC-EFGH

Inversion Chromosome segment breaks off Segment flips around backwards Segment reattaches ABCD-EFGH ABDC-EFGH

Duplication Occurs when a gene sequence is repeated ABCD-EFGH ABCDBCD-EFGH

Duplication Occurs when a gene sequence is repeated ABCD-EFGH ABCDBCD-EFGH

Translocation Involves two chromosomes that aren’t homologous Part of one chromosome is transferred to

Translocation Involves two chromosomes that aren’t homologous Part of one chromosome is transferred to another chromosomes ABCD-EFGH WXY-Z ABCD-EF WXY-ZGH

Translocation

Translocation

Nondisjunction Failure of chromosomes to separate during meiosis Causes gamete to have too many

Nondisjunction Failure of chromosomes to separate during meiosis Causes gamete to have too many or too few chromosomes Disorders: Down Syndrome – three 21 st chromosomes Turner Syndrome – single X chromosome Klinefelter’s Syndrome – XXY chromosomes

Chromosome Mutation Animation

Chromosome Mutation Animation

Chromosome Mutations Down Syndrome Chromosome 21 does not separate correctly. Trisomy 21 They have

Chromosome Mutations Down Syndrome Chromosome 21 does not separate correctly. Trisomy 21 They have 47 chromosomes in stead of 46. Children with Down Syndrome develop slower, may have heart and stomach illnesses and vary greatly in their degree of intelligence. Similar facial features

Chromosome Mutations Cri-du-chat Deletion of material on 5 th chromosome Characterized by the cat-like

Chromosome Mutations Cri-du-chat Deletion of material on 5 th chromosome Characterized by the cat-like cry made by cri-du-chat babies Varied levels of mental handicaps

Sex Chromosome Abnormalities Klinefelter’s Syndrome XXY, XXXY Male Sterility Small testicles Breast enlargement

Sex Chromosome Abnormalities Klinefelter’s Syndrome XXY, XXXY Male Sterility Small testicles Breast enlargement

Sex Chromosome Abnormalities XYY Syndrome Normal male traits Often tall and thin Associated with

Sex Chromosome Abnormalities XYY Syndrome Normal male traits Often tall and thin Associated with antisocial and behavioral problems*

Sex Chromosome Mutations Turner’s Syndrome X Female sex organs don't mature at adolescence sterility

Sex Chromosome Mutations Turner’s Syndrome X Female sex organs don't mature at adolescence sterility short stature

Sex Chromosome Mutations XXX Trisomy X Female Little or no visible differences tall stature

Sex Chromosome Mutations XXX Trisomy X Female Little or no visible differences tall stature learning disabilities limited fertility

KARYOTYPE ANALYSIS

KARYOTYPE ANALYSIS

 Karyotype Pictures of paired human chromosomes arranged by size, used to identify abnormalities

Karyotype Pictures of paired human chromosomes arranged by size, used to identify abnormalities in fetuses Cells from an amniotic fluid sample are cultured, stained & photographed

 1) Autosomes all the chromosomes except the sex chromosomes (in humans, there are

1) Autosomes all the chromosomes except the sex chromosomes (in humans, there are 22 pair) 2) Sex chromosomes The sex-determining chromosomes, the X&Y

Normal Male 2 n = 46 28

Normal Male 2 n = 46 28

Normal Female 2 n = 46 29

Normal Female 2 n = 46 29

Male, Trisomy 21 (Down’s) 2 n = 47 30

Male, Trisomy 21 (Down’s) 2 n = 47 30

Female Down’s Syndrome 2 n = 47 31

Female Down’s Syndrome 2 n = 47 31

Klinefelter’s Syndrome 2 n = 47 32

Klinefelter’s Syndrome 2 n = 47 32

Turner’s Syndrome 2 n = 45 33

Turner’s Syndrome 2 n = 45 33