Loci and the Human Karyotype Biology Unit 6 2014-2015

Chromosomes Karyotype: ordered display of an individual’s chromosomes. Collection of chromosomes from mitotic cells. Staining can reveal visible band patterns, gross anomalies.

Karyotyping Meiosis KM

Karyotypes arrange chromosomes in order by size: Largest to smallest

Chromosomes Some large like #1 Some small like #22

Homologous pairs Same Length Centromere in same location Same bands (genes)

Centromere Position The centromere is not exactly in the center of the chromosome “p” arm: (p=petite) the shorter arm of the chromosome “q” arm: the longer arm of the chromosome

Locus (plural=loci) The position that a given gene occupies on a chromosome. (Its like an address for your genes) Written like this: 15p23

Example: 15p23=Chrom 15 small arm, 23rd band from the centromere

Trisomy: *Having 3 chromosomes of each kind instead of 2 *Normally trisomy results in death. 1 Example

Down Syndrome: a genetic condition in which the individual has 3 copies of the 21st chromosome. Genotype: 3 copies of 21st chromosome

Lt Olive 2p18 2q21 Ssss 2 Locus Allele My Geno. My Pheno Gene Chrom # Gene Description Locus Allele My Geno. My Pheno Lt Olive S = Dark s= Light SSSS= Dark SSSs= Fairly Dark SSss= Olive Ssss = Light Olive ssss = Lightest White Skin Color Polygenic 2p18 2q21 Ssss 2 S s s s

4p20 4 Aa Some Acne Locus Allele My Geno. My Pheno A=Acne Acne Chrom # Gene Description Locus Allele My Geno. My Pheno 4p20 4 A=Acne a=No Acne Aa Some Acne Acne Polygenic Incomplete Dominance AA=Lots Aa=some aa= none A a

nn 4p19 Locus Allele My Geno. My Pheno No Cleft N = Cleft n= no cleft Chrom # Gene Description Locus Allele My Geno. My Pheno N = Cleft n= no cleft 4 Cleft Chin Regular Dominance 4p19 nn No Cleft n n

7p15 Bb Locus Allele My Geno. My Pheno Light Brown 7 Eye color Chrom # Gene Description Locus Allele My Geno. My Pheno 7 Eye color Incomplete Dominance 7p15 B=Brown b=Blue Light Brown Bb BB=Brown Bb=Light Brown, Hazel, Green bb=blue B b

7p11 Hh Locus Allele My Geno. My Pheno Hair Color Incomplete Dominance Chrom # Gene Description Locus Allele My Geno. My Pheno Hair Color Incomplete Dominance 7p11 H=Brown/Black h=blonde Hh Light Brown 7 HH=Brown/Black Hh=Light Brown hh=Blonde H h

No CF FF 7q25 Locus Allele My Geno. My Pheno 7 Cystic Fibrosis Chrom # Gene Description Locus Allele My Geno. My Pheno 7 Cystic Fibrosis Autosomal recessive 7q25 No CF F = No CF f = CF FF F F

Aa 7q11 Locus Allele My Geno. My Pheno Some acne Acne 7 A= Acne Chrom # Gene Description Locus Allele My Geno. My Pheno 7q11 Acne Polygenic Incomplete Dominance 7 A= Acne a = no Acne Some acne Aa A a

o ii 9q34 Locus Allele My Geno. My Pheno IA=A Blood Type IB=B 9 Chrom # Gene Description Locus Allele My Geno. My Pheno IA=A IB=B i=O Blood Type A & B Codom. O=Recessive 9 9q34 ii o i i

Rr Rh+ 9q30 Locus Allele My Geno. My Pheno 9 Rh Factor Chrom # Gene Description Locus Allele My Geno. My Pheno 9 Rh Factor Normal Dominance 9q30 R = +Rh r = - Rh Rr Rh+ R r

ff 12p5 Locus Allele My Geno. My Pheno Freckles Normal Dominance Chrom # Gene Description Locus Allele My Geno. My Pheno Freckles Normal Dominance 12p5 F = Freckles f= no freckles 12 ff No Freckles f f

cc 12q24 Locus Allele My Geno. My Pheno Hair Type Incomplete Dominance Chrom # Gene Description Locus Allele My Geno. My Pheno Hair Type Incomplete Dominance 12q24 CC= Curly cc = Straight Cc=Wavy 12 cc Straight C C

No TS TT 15q23 Locus Allele My Geno. My Pheno Tay-Sachs T = No TS 15 Chrom # Gene Description Locus Allele My Geno. My Pheno Tay-Sachs Autosomal recessive 15q23 T = No TS t = TS No TS 15 TT T T

Dd 16p10 Locus Allele My Geno. My Pheno 16 Dimples Normal Dominance Chrom # Gene Description Locus Allele My Geno. My Pheno 16 Dimples Normal Dominance 16p10 Dd D=Dimples d = No Dimples Dimples D d

XBY XAY Locus Allele My Geno. My Pheno 23 Color Blind Hemophilia Chrom # Gene Description Locus Allele My Geno. My Pheno XBY XAY B= Not Colorblind b = Colorblind 23 Color Blind Hemophilia A= No Hemophilia a = Hemophilia B A