arabera Rida Sorfina 4 years ago
714
Honelako gehiago
ANEUPLOIDY
chromosomal EXTRA or MISSING from normal set
cause-non-disjunction during meiosis (anaphaseI,II) non-disjunction-failure of a homologous chromosomes or sister chromatid to separate and move to opposite poles
occur in autosome and sex-chromosomes
eg: 2n-1monosomy,2n+1trisomy
EUPLOIDY/POLYPOIDY
has more than two sets of chromosomes (more common in plant)
3n,4n,5n,
occur naturally(by non-disjunction or induction)
form new species better qualities
alloploidy
individual has more than two chromosomes sets that derived from different species
autoploidy
individual has more than two chromosomes sets that all derived from same species
More than one nucleotide breaks, rotate 180 and reattached to the DNA
Loss of one or more nucleotide pair from the DNA
Addition of one or a more nucleotide pair into the DNA
frameshift mutation
one nucleotide pair is replaced with another nucleotide pair in the DNA sequence
lead- silent, missense, nonsense mutation
NONSENSE MUTATION
changes mRNA into a stop codon
translation terminated produce shorter polypeptide
lead to non-functional proteins
MISSENSE MUTATION
cause frameshift mutation
amino acid changes to another amino acid
results in ONE WRONG CODON and ONE WRONG AMINO ACID in polypeptide
less active protein
eg: SICKLE CELL ANEMIA(RBC shape like a crescent)
symptoms sickle cell anemia
*Hb-stiff, tend to accumulate at blood capillary *fatal form of anemia *organ damages *physical weakness
DNA- CTT replaced CAT mRna-codon GAA replaced GUA polypeptide- glutamic acid replaced valine
SILENT MUTATION
base substitution nucleotide pair of DNA has no effect on the encoded protein
change in nucleotide but translated same amino acid
changes codon on mRNA codes for the same amino acid
