GENETIC DISORDERS. ____________________________ –change in a gene resulting in change in genetic information may be spontaneous or caused by a mutagen.

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Presentation transcript:

GENETIC DISORDERS

____________________________ –change in a gene resulting in change in genetic information may be spontaneous or caused by a mutagen _____________________ mutations are usually not noticed ______________________________ mutations are more severe Not all mutations are bad!

______________________ Misplacement, insertion or deletion of one base pair May result in incorrect amino acid May result in shift of reading frame Congenital Defects: Visible at birth(club foot, spina bifida, congenital heart defects) Caused by environmental factors (FAS, German measles) Inherited Sickle Cell Anemia, Cystic Fibrosis

__________________ Part of chromosome is flipped around 180° from its normal orientation. Happens when chromosome breaks occur. Broken piece may reattach, but not necessarily in the same orientation as before

__________________ Detachment of a segment of a chromosome, and reattachment to another non-homologous chromosome. Some genes wind up on a completely different chromosome

ANOMALIES OF CHROMOSOME NUMBER ________________ is common in plants Gametes don’t reduce chromosome # Result in cells with multiple copies of the genome

ANOMALIES OF CHROMOSOME NUMBER __________________ – more common in humans Usually lethal before or shortly after birth Monosomic and Trisomic

_________________________ Occurs when homologous chromosomes fail to separate after synapsis Most nondisjunction events are lethal to the fetus

_______________________ Results from a third copy of chromosome 21 Called a trisomy Individuals have 47 chromosomes in every body cell

SEX CHROMOSOME NONDISJUNCTION DISORDERS ______________________________ Occurs when nondisjunction causes a gamete to have a missing sex chromosome (X O) Sterile females 1 in live births

SEX CHROMOSOME NONDISJUNCTION DISORDERS ________________________________ Genotype of XXY (extra sex chromosome) Sterile males, breast development 1 in 800 live births

SEX CHROMOSOME NONDISJUNCTION DISORDERS ½ ½ ½ gamete lacking a sex chromosome XO ¼ Turner’s syndrome YO ¼ Will not survive (LETHAL CONDITION) ½ gamete formed from nondisjunction XXX ¼ “super female” usually normal XXY ¼ Klinefelter’s syndrome XY XY O XX