Gene A unit of heredity that controls the development of one trait Made of DNA

Allele Member of a paired gene Dominant alleles are expressed One allele comes from each parent Dominant alleles are expressed Recessive alleles are not expressed in the presence of a dominant allele Recessive alleles are only expressed if both recessive alleles are present

Examples of Alleles DD = Dwarfism Dd = Dwarfism dd = Normal height Normal height = d DD = Dwarfism Dd = Dwarfism dd = Normal height Dwarf Band

Genotype Genetic make up Represented by alleles DD & Dd are genotypes for dwarfism

Phenotype A trait Genotype determines the phenotype Dwarfism is a phenotype

Codominant Two different alleles are both dominant A = allele for type A blood B = allele for type B blood AB = results in type AB blood

Karyotype Picture of chromosomes from an individual

Homologous Chromosomes Chromosomes of the same pair Karyotypes are usually arranged with homologous chromosomes paired together

Mutation Change in a gene or chromosome Causes an abnormal trait

Mutagen Agent that causes mutations Cigarette smoke Pesticides X-rays Ulatraviolet light Nuclear radiation

Sex Chromosomes Male have Xy Females have XX Male gametes have either X or y Females have XX Female gametes have X

Autosomes Chromosomes 1-22

X-Linked (vs Y- linked)Traits Why are there more X-linked that Y- linked disorders? Who suffers more frequently from sex-linked disorders? Why?

Which karyotype is which? A B

Trisomy 21: Down Syndrome Large tongue Flat face Slanted eyes Single crease across palm Mental retardation Some are not

Maternal Age & Down Syndrome

Trisomy 18: Edward Syndrome Heart defects Displaced liver Low-set ears Abnormal hands Severe retardation 98% abort Lifespan < 1 year

Trisomy 13: Patau Syndrome Cleft lip and palate Extra fingers & toes polydactylism Defects Heart Brain Kidneys Most abort Live span < 1 month

Klinefelter Syndrome Breast development Small testes Sterile Low intelligence Not retarded Klinefelter Website

Turner Syndrome Short Not go through puberty Produce little estrogen Sterile Extra skin on neck

Fetal Testing

Heterozygote Phenotype Complete Dominance Incomplete Dominance CO-Dominance Multiple Alleles Sex-Linked Traits Number of Alleles 2 3 Example of Alleles A a A’ B IA IB i XA Xa Heterozygote Phenotype Dominant parent Neither parent Both parents Dominant OR both parents depends Number of genotypes 6 5 Possible Genotypes AA, Aa, aa AA, AA’, A’A’ AA, BB, AB IA IA, IB IA, IA I, IB IB, IBi, ii, XA XA, XA Xa, XaXa, XAY, XaY, Number of phenotypes 4 Possible phenotypes A, B A, A’ , AA’ A, B, AB A, B, AB, O A, a Classical Example Pea plants 4 o clock flowers Roan cows ABO Blood group Hemophilia Color blindness Example Blue eyes X purple eyes = blue eyes Blue eyes X purple eyes = green eyes Blue eyes X purple eyes = blue and purple eyes various Males determines daughters and mother determines son

A man & woman are both carriers (heterozygous) for albinism A man & woman are both carriers (heterozygous) for albinism. What is the chance their children will inherit albinism?

AA = Normal pigmentation Aa = Normal pigmentation (carrier) aa = Abino Man = Aa Woman = Aa A A a a

A a A Aa AA a Aa aa

AA Aa aa Genotypes Phenotypes Probability 1 AA, 2Aa, 1aa 3 Normal 1 Albino Probability 25% for albinism

A man & woman are both carriers (heterozygous) for PKU disease A man & woman are both carriers (heterozygous) for PKU disease. What is the chance their children will inherit PKU disease?

PP = Normal Pp = Normal (carrier) pp = PKU disease P p PP Pp pp P p

PP Pp pp Genotypes Phenotypes Probability 1 PP, 2Pp, 1pp 3 Normal 1 PKU disease Probability 25% for PKU disease

A man with sickle cell anemia marries a woman who is a carrier A man with sickle cell anemia marries a woman who is a carrier. What is the chance their children will inherit sickle cell anemia?

SS = Normal Ss = Normal (carrier) ss = Sickle Cell S s s Ss ss s

Genotypes ss Ss Phenotypes Probability 2 Ss, 2ss 2 Normal (carriers) 2 Sickle cell Probability 50% for Sickle cell

A man with heterozygous dwarfism marries a woman who has normal height A man with heterozygous dwarfism marries a woman who has normal height. What is the chance their children will inherit dwarfism? Dwarfism is dominant.

DD = Dwarf Dd = Dwarf dd = Normal d d D Dd dd d

Genotypes Dd Phenotypes dd Probability 2 Dd, 2dd 2 Normal 2 Dwarfs 50% for Dwarfism

XH XH = Normal Female XH Xh = Normal Female (Carrier) Xh Xh = Hemophilic Female XHy = Normal Male Xhy = Hemophiliac Male

A man with hemophilia marries a normal woman who is not a carrier A man with hemophilia marries a normal woman who is not a carrier. What is the chance their children will inherit hemophilia? Hemophilia is X-linked recessive.

XH XH Xh XH Xh XH Xh XHy XHy Xh XH = Normal Female XH Xh = Normal Female (Carrier) Xh Xh = Hemophilic Female XHy = Normal Male Xhy = Hemophiliac Male XH XH Xh XH Xh XH Xh XHy y XHy

XH Xh XH Xh XHy Genotypes Phenotypes y Probability 2 XH Xh, 2XHy 2 Carrier Females 2 Normal Males Probability O% for Hemophilia

A normal man marries a normal woman who is a carrier for hemophilia A normal man marries a normal woman who is a carrier for hemophilia. What is the chance their children will inherit hemophilia?

XH Xh XH XH XH XH Xh XHy Xhy Xh XH = Normal Female XH Xh = Normal Female (Carrier) Xh Xh = Hemophilic Female XHy = Normal Male Xhy = Hemophiliac Male XH Xh XH XH XH XH Xh XHy Xhy y

XH Xh XH XH , XH Xh, XHy, Xhy XH XH XH XH Xh XHy Xhy Genotypes Phenotypes 2 Normal Females 1 Normal Males 1 Male Hemophiliac XHy y Xhy Probability 50% for Male Hemophilic 0% for Female Hemophilic