(Non-Mendelian Genetics) Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Sometimes inheritance does not follow Mendel’s rules (Non-Mendelian Genetics) X = X = X = X = Skin Tone Eye Color

The heterozygous phenotype is a blend of the dominant and recessive Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Incomplete Dominance The heterozygous phenotype is a blend of the dominant and recessive R R r Rr Rr r Rr Rr R r R RR Rr r Rr rr

Both alleles are expressed Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Codominance Both alleles are expressed rr R R RR r Rr Rr r Rr Rr Rr Rr Rr Rr R r R rr RR Rr RR r Rr Rr rr Rr

Codominance Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Codominance

Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Population with a high risk of contracting Malaria Population affected with Sickle Cell Anemia Malaria Animation

There are more than 2 alleles for a particular trait Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Multiple Alleles There are more than 2 alleles for a particular trait For blood type in humans there are 3 alleles A B O (ABO blood type) A & B are Co-Dominant & O is Recessive

Blood Types Type A A B A & AB A & O Type B B A B & AB B & O Type AB Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Can Receive From: Blood Types Can Give to: Antigen Antibody Type A A B A & AB A & O Type B B A B & AB B & O Type AB A & B none AB All Type O none A & B All O

Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance What are the possible blood types for the children of a heterozygous type A woman and a heterozygous type B man? Phenotype Genotype Type A IA IA or IA i Type B IB IB or IB i IA i IA IB IB i IB Type AB IA IB i IA i i i Type O i i

Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance What are the possible blood types for the children of a heterozygous type A woman and a heterozygous type B man?

more than one pair of genes code for a particular trait Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Polygenic Traits more than one pair of genes code for a particular trait ---------------------- The occurrence of the phenotypes of a polygenic trait usually form a bell curve

Sex determination in humans Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Sex determination in humans

Sex determination in humans Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Sex determination in humans XX x XY X Y X XX XY X XX XY

Traits found on the sex chromosomes Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Sex-Linked Traits Traits found on the sex chromosomes More traits are found on the X-chromosome than the Y

Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Sex-Linked Traits Red-green colorblindness and hemophilia are x-linked, recessive disorders

Females are far less likely to have an x-linked recessive disorder. Ch.11 – Complex Inheritance & Human Heredity 11.2 – Complex Patterns of Inheritance Sex-Linked Traits Females are far less likely to have an x-linked recessive disorder. XB Y A cross between a carrier female and a male with normal vision will lead to the following: XB XBXB XBY Xb XBXb XbY

Genetic Disorders Autosomal Recessive Disorders. Cystic Fibrosis Ch.11 – Complex Inheritance & Human Heredity 11.1 – Human Heredity Genetic Disorders Autosomal Recessive Disorders. Cystic Fibrosis Defective membrane protein leads to digestive & Respiratory failures Albinism Little to no melanin production which causes skin and eye damage from UV rays Tay-Sachs Inability to break down fatty substances leads to a buildup in the brain and mental disabilities

Autosomal Dominant Disorders. Ch.11 – Complex Inheritance & Human Heredity 11.1 – Human Heredity Genetic Disorders Autosomal Dominant Disorders. Decline of mental and neurological function – Symptoms usually appear in middle age Huntingtons Achondroplasia Dwarfism

Pedigree Analysis 11.1 – Human Heredity Ch.11 – Complex Inheritance & Human Heredity 11.1 – Human Heredity Pedigree Analysis (Inter-family) (The subject being studied)

Which shows a dominant and which a recessive autosomal disorder? Ch.11 – Complex Inheritance & Human Heredity 11.1 – Human Heredity Which shows a dominant and which a recessive autosomal disorder? Recessive Dominant (or recessive)

Sex-Linked Recessive 11.1 – Human Heredity Ch.11 – Complex Inheritance & Human Heredity 11.1 – Human Heredity Sex-Linked Recessive

What are the genotypes for Ch.11 – Complex Inheritance & Human Heredity 11.1 – Human Heredity What are the genotypes for I-1 & I-2? II-1 & II-2? III-1, III-2 & III-3? Aa Aa A? A? aa A? A? Aa Aa Aa

Ch.11 – Complex Inheritance & Human Heredity When carriers are shown on a pedigree you know all genotypes (sometimes carriers are shown sometimes they are not) XAXa XAY XAXA XaY

Chromosomal Disorders Ch.11 – Complex Inheritance & Human Heredity 11.3 – Chromosomes & Human Heredity Chromosomal Disorders Down Syndrome Kleinfelter’s Syndrome

Nondisjunction 11.3 – Chromosomes & Human Heredity Ch.11 – Complex Inheritance & Human Heredity 11.3 – Chromosomes & Human Heredity Nondisjunction

Trisomy will usually cause death very early in pregnancy. Ch.11 – Complex Inheritance & Human Heredity 11.3 – Chromosomes & Human Heredity Trisomy will usually cause death very early in pregnancy. Trisomy 13,15,18, & 22 have been documented (most die before age 1) Trisomy 21 Down Syndrome abnormal facial appearance, high likelihood of mental retardation (degree varies considerably), and increased likelihood of developing leukemia and Alzheimer’s disease

Nondisjunction in Sex Chromosomes Klinefelter’s Syndrome Ch.11 – Complex Inheritance & Human Heredity 11.3 – Chromosomes & Human Heredity Nondisjunction in Sex Chromosomes Turner’s Syndrome Underdeveloped reproductive organs & infertility. Short stature and decreased mental function Klinefelter’s Syndrome Underdeveloped reproductive organs & infertility. May also cause Enlarged breasts & a decrease in mental function.