Nondisjunction Homework for 111314 Fill out notes on

Nondisjunction • Although the events of meiosis usually proceed accurately, sometimes an accident occurs

Nondisjunction • The zygote that has been created will have an extra or missing

Nondisjunction Monosomy - the presence of only one chromosome from a pair in a

Karyotypes • When you are born, doctors take a sample of your blood and

Karyotypes Homologous chromosomes are paired up, then they are put in order from the

Karyotypes Everyth ing ok ay her e ? ? r de n e tg

Down’s syndrome Everyth ing ok ay her e? ? • decreased muscle tone at

Turner’s syndrome Everyth ing ok ay her e? ? • short stature (affects almost

Everyth Kleinfelter’s syndrome ing ok ay her e? ?

Kleinfelter’s syndrome • No symptoms - some men are unaware they have an extra

Everyth Patau’s syndrome ing ok ay her e? ?

Patau’s Syndrome • Mental retardation, severe • Seizures • Small head • Scalp defects

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Nondisjunction Homework for 11/13/14 Fill out notes on the back of page 34, which is the Cell Division Venn Diagram

Nondisjunction • Although the events of meiosis usually proceed accurately, sometimes an accident occurs and the chromosomes fail to separate correctly. This is known as nondisjunction.

Nondisjunction • The zygote that has been created will have an extra or missing chromosome. This would result in an inherited genetic disorder. o In most cases, the presence of an additional chromosome or missing chromosome results in the death of the zygote.

Nondisjunction Monosomy - the presence of only one chromosome from a pair in a cell's nucleus. Trisomy – the presence of three chromosomes instead of 2 in a cell’s nucleus.

Karyotypes • When you are born, doctors take a sample of your blood and create a karyotype. This will enable the doctor to see if you have any additional or missing chromosomes. • A karyotype is a standardized arrangement of all the chromosomes of a cell.

Karyotypes Homologous chromosomes are paired up, then they are put in order from the LARGEST chromosome pair to the smallest.

Karyotypes 2 xc hrom o = somes GIRL

Karyotypes Everyth ing ok ay her e ? ? r de n e tg a h W 2 different sized sex chromosomes = male

Down’s syndrome Everyth ing ok ay her e? ? • decreased muscle tone at birth • asymmetrical or odd-shaped skull • round head with flat area at the back of the head • slanting eyes • small mouth with protruding tongue • single crease on the palm • slowed growth and development • delayed mental and social skills

Turner’s syndrome Everyth ing ok ay her e? ? • short stature (affects almost all girls with Turner, to different degrees) • failure of ovaries to develop (90 -95% of girls) • webbed neck (25%) or short neck (40%) • abnormal fingernails and toenails (70%) • hearing disorders (50 -90%) • frequent ear infections in childhood (75%)

Turner’s syndrome

Everyth Kleinfelter’s syndrome ing ok ay her e? ?

Kleinfelter’s syndrome • No symptoms - some men are unaware they have an extra chromosome • Enlarged male breasts - only severe in about 10% of cases • Sparse facial hair • Sparse body hair • Inability to produce sperm • Tallness - more likely to be taller than non-XXY males. • Thinness • Normal intelligence • Language impairment • Delayed language

Kleinfelter’s syndrome

Everyth Patau’s syndrome ing ok ay her e? ?

Patau’s Syndrome • Mental retardation, severe • Seizures • Small head • Scalp defects (absent skin) • Small eyes (microphthalmia) • Cleft lip and/or palate