1 Human Genetics Biology: Exploring Life Campbell, Williamson, Heyden Prentice Hall

The nucleus contains an information rich- genome.

3 DNA Packing in a Single Cell 1 chromosome = 1 DNA strand Genome Order of bases in DNA Histones DNA wraps around tiny proteins

4 Human Genome Project sequence functions Determine the sequence and functions of all human chromosomes “ rough-draft ” done in 2000 Introns vs exons Coding vs non-coding

Accidents affecting chromosomes can cause disorders.

6 Down Syndrome Abnormal chromosomes Miscarriage Trisomy 21 Down Syndrome Three chromosomes 21 Characteristics Facial features Below-average height Heart defects Immune dysfunction Mental disability

7 Nonseparation of Chromosomes Nondisjunction Failure of chromosomes to separate Causes? Not known Older women

8 Damaged Chromosomes Duplication Part of chromosome is duplicated Deletion Fragment is lost Inversion Reversing a fragment Translocation Fragment attaches to non-homologous

9 Jumping Genes Barbara McClintock 1940 ’ s genes Single genes can move around Transposons Genetic element that moves from one location to another in a genome

Mendel ’ s principles apply to humans.

11 Human Pedigrees Analyze patterns of inheritance Pedigree Family tree that records occurrences of traits Use the pedigree Attached earlobe is recessive Not enough info

12 Disorders Inherited as Recessive Traits Range of severity Albinism Carrier Has copy of allele but does not show symptoms Tay-Sachs Major nerve damage Cystic Fibrosis 1/25 from European decent Defective protein secretes excessive mucus

13 Disorders Inherited as Dominant Traits Examples Extra fingers and toes Achondroplasia Heterozygous Two copies – fatal 99.99% population has homozygous recessive Recessive alleles sometimes common Death Huntington's Disease Middle-age nervous system degeneration Chromosome #4

14 Sex-linked Disorders Most located on X chromosome ♂ only needs one “ bad ” allele ♀ needs both “ bad ” alleles

15 Predicting and Treating Genetic Disorders Genetic counselor Collects, analyzes and explains patterns of inheritance Tests before birth Trisomy 21 Tests after birth Phenylketonuria (PKU) Causes metal disability

Genetic Changes contribute to cancer.

17 Cancer Genes Pics Breast cancer Brain cancer Immune system attacks cancer Growth factor Initiate cell division Tumor-suppressor genes Proteins to stop cell division Oncogene Cancer causing gene

18 “ Inherited ” Cancer Always is from damaged or changed DNA Not passed from parent to child if non-sex cell Mutated tumor- suppressor-gene BRCA1 More likely to form breast cancer

19 Permission Statement Restricted to the use of New Berlin Eisenhower High School (New Berlin, WI) Students, Faculty and Staff. Contact the Science Department for usage permissions. © 2006