Chapter 11 Complex Inheritance and Human Heredity Section 1: Basic Patterns of Human Inheritance Section 2: Complex Patterns of Inheritance Section 3: Chromosomes and Human Heredity

True or False? The father determines the gender of the child. Individuals can transmit characteristics to their offspring which they themselves do not show. Identical twins are always of the same gender. If someone looks more like 1 parent than the other, did that person inherit more genes from that parent?

4 Recessive Genetic Disorders Basic Patterns of Human Inheritance 4 Recessive Genetic Disorders A recessive trait is expressed when the individual is homozygous recessive for the trait.

1. Cystic Fibrosis (CF) Affects the mucus-producing glands, digestive enzymes, and sweat glands Without sufficient chloride ions in the cells, a thick mucus is secreted. Treatments are physical therapy, and medications. Diagnosed in the 1st year of life.

2. Albinism Caused by altered genes, resulting in the absence of the skin pigment melanin in hair and eyes White hair Very pale skin Pink eyes Brazilian mother who has three white children

3. Galactosemia (similar symptoms to lactose intolerant) The body cannot digest galactose. Children must be put on a special diet. Caused by an enzyme deficiency.

4. Tay-Sachs Disease Caused by the absence of the enzymes responsible for breaking down fatty acids. They accumulate in the brain nerve cells and cause mental deterioration. Kids die at a young age. Occurs more in the Jewish community.

2 Dominant Genetic Disorders p. 298 1. Huntington’s disease affects the nervous system. Diagnosed 40-50 years old. 2. Achondroplasia (dwarfism) causes small body size and limbs that are comparatively short.

Doctor Vitaliy Veklich and children with diagnosis achondroplasia on different stages of limb lengthening In comparison adults it is possible to perfrom limb lenthening for children few times in the ade 4-6 and 14-15 years old. At age 4-6 years old: 1 stage - lengthening of both tibia (6-7 cm) 2 stage - lengthening of both femur (6-7 cm) 3 stage - lengthening of both humeral bone (5 cm) Each stage needs 2,5 months of limb lengthening and 2,5 months for bone consolidation. The interval between stages is 2-3 months. At age 14-15 years old: 1 stage - lengthening of both tibia (6-7 cm) 2 stage - lengthening of both femur (6-7 cm) 3 stage - lengthening of both humeral bone (5 cm) Totally it is possible to increase height of a child with diagnosis achondroplasia 24-28 cm taller.

Why are recessive disorders more common than dominant disorders? If the dominant trait interferes with survival, the gene probably won’t get passed on. When it is recessive, carriers do not display the disorder. Many people carry recessive alleles without being affected by the disorder.

Pedigrees A diagram that traces the inheritance of a particular trait through several generations –shows the phenotype. Sometimes you can figure out the genotype.

Pedigrees Diagrams used to trace the inheritance of traits across generations 2 1 3 4 I II III Mary Samuel Thomas Susan Robert Julia Jennifer Sean Michael

Identifying Individual and their symbols 1 2 Four Generations II-4 and II-5 have THREE KIDS I Seven Individuals 1 7 4 5 II 8 1 III IV

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60 minutes genetic disorder: http://www.cbsnews.com/news/breeding-out-disease-with-reproductive-genetics/