Pick up warm-up from front Pick up warm-up from front table.table.

Complete warm-up first!Complete warm-up first! When finished…get out sponge bob When finished…get out sponge bob

worksheet. Do you have any questions???worksheet. Do you have any questions???

You will need a RING today.You will need a RING today.

Projects are due Projects are due ThursdayThursday Genetics Unit Test is Genetics Unit Test is FridayFriday I will be here after school Wed & ThurI will be here after school Wed & Thur

KaryotypesKaryotypesWhat are they??What are they??

How do we use them?How do we use them?

Normal Karyotype--maleNormal Karyotype--male

Normal Karyotype--femaleNormal Karyotype--female

Is this person female or Is this person female or male?male?

Hold up a red or blue card on your Hold up a red or blue card on your ring.ring.

How are DNA samples How are DNA samples obtained for karyotypes?obtained for karyotypes?

AmniocentesisAmniocentesis: obtaining : obtaining amniotic fluid which has cells amniotic fluid which has cells

from the fetusfrom the fetus

Chorionic villi samplingChorionic villi sampling: : removing cells from the chorion removing cells from the chorion

with fetal tissuewith fetal tissue

What to look for?What to look for? Are there 46 chromosomes? Are there 46 chromosomes?

Are there 2 identical pairs of each Are there 2 identical pairs of each autosome and 2 sex chromosomes? autosome and 2 sex chromosomes?

Are there any rearrangements Are there any rearrangements between chromosomes or large between chromosomes or large deletions? deletions?

Trisomy 21 or Down Trisomy 21 or Down SyndromeSyndrome

1 in 700 births

47 chromosomesXY or XX

#21 Trisomy Nondisjunction

3

Correlation between mother’s Correlation between mother’s age and Trisomy 21 incidenceage and Trisomy 21 incidence

Turners syndromeTurners syndromecaused by caused by

NondisjunctionNondisjunction

Monosomy

XXY Male (Extra X)XXY Male (Extra X)Male or Female? Show red or blue card on ring.

Is this a normal karyotype??

Klinefelter syndromeKlinefelter syndrome XXY on 23XXY on 23rdrd pair pair Male with some female Male with some female

characteristicscharacteristics small testes that do not produce as small testes that do not produce as

much testosterone as usualmuch testosterone as usual Delayed pubertyDelayed puberty Reduced body hairReduced body hair infertilityinfertility

Deletion—18 Q Deletion Deletion—18 Q Deletion SyndromeSyndrome

If there are chromosomal If there are chromosomal number abnormalities, how do number abnormalities, how do they form?they form? MeiosisMeiosis: the process of creating : the process of creating

sperm or egg from a diploid cellsperm or egg from a diploid cell

If there is a mistake when If there is a mistake when chromosomes are separating, then chromosomes are separating, then the resulting sperm or egg will have the resulting sperm or egg will have too many or too few chromosomes.too many or too few chromosomes.

NondisjunctionNondisjunction

What we can’t seeWhat we can’t see Individual DNA strands or genesIndividual DNA strands or genes

The number of genes in any given The number of genes in any given area of a chromosome. area of a chromosome.

The presence or location of small The presence or location of small mutations. (Scientists cannot predict mutations. (Scientists cannot predict diseases caused by small mutations diseases caused by small mutations within genes.within genes.

Other Other chromosomal chromosomal disorders that disorders that

can arise?can arise?

Problems with Problems with chromosomeschromosomes

DuplicationDuplication: copied parts of : copied parts of chromosome chromosome

A

B

C

D

A

B

B

B

C

D

Problems with Problems with chromosomeschromosomes

DeletionDeletion: missing parts of : missing parts of chromosomechromosome

A

B

C

D

A

D

Problems with Problems with chromosomeschromosomes

InversionInversion: parts of chromosome : parts of chromosome tchedtched

A

B

C

D

A

C

B

D

Chromosomal mutationsChromosomal mutationsDeletion

Duplication

Inversion

Translocation

Human genetic disorders from Human genetic disorders from deleterious genesdeleterious genes

Sometimes the alleles inherited Sometimes the alleles inherited contribute to disorders and not from the contribute to disorders and not from the number or shape of the chromosomes.number or shape of the chromosomes.

1.1. Sex-linkedSex-linked: genes found on X or Y : genes found on X or Y chromosomechromosome

2.2. RecessiveRecessive: requires 2 allele copies to : requires 2 allele copies to express disorderexpress disorder

3.3. DominantDominant: requires only 1 allele copy to : requires only 1 allele copy to express disorderexpress disorder

Recessive disordersRecessive disorders

Dominant disorderDominant disorder

Mile-a-minute

Sex ChromosomesTrisomyKleinfelter’s SyndromeInsertionNondisjunction

Mile-a-minute

MonosomyDown SyndromeKaryotypeInversionNondisjunction in Meiosis I

Mile-a-minute

DeletionTurner’s SyndromeNondisjunction in Meiosis IIAutosomeSex-linked trait

Mile-a-minute

Incomplete dominanceCarrierPedigreeCodominanceHeredity