 FOLLOWING PATTERNS OF INHERITANCE

Humans cannot undergo breeding experiments for use in genetic studies – ethical implications

FOLLOWING PATTERNS OF INHERITANCE PEDIGREE – a type of flowchart that uses symbols to show the inheritance patterns of traits in a family over many generations - a way to analyze how traits run in a family - a way to visualize patterns of inheritance - can uncover genotypes of particular family members

PEDIGREE

AUTOSOMAL INHERITANCE AUTOSOMAL INHERITANCE: inheritance of traits whose genes are found on autosomes in humans(chromosomes 1-22) a) AUTOSOMAL DOMINANT: the disease causing allele is dominant and is present in an individual with one or both copies of the allele b) AUTOSOMAL RECESSIVE: the disease causing allele is recessive and both copies of the allele is required

AUTOSOMAL INHERITANCE AUTOSOMAL INHERITANCE PATTERNS (Page 220) CHROMOSOME NUMBER CONDITIONINHERITANC E PATTERN DESCRIPTION 4Huntington disease Autosomal dominant Loss of muscle control and decline in mental ability 7Cystic fibrosis Autosomal recessive Thick mucus build up in lungs making breathing difficult 11Sickle cell anemia Autosomal recessive Red blood cells irregularly shaped

AUTOSOMAL INHERITANCE AUTOSOMAL INHERITANCE PATTERNS (Page 220) CHROMOSOM E NUMBER CONDITIONINHERITANC E PATTERN DESCRIPTION 12PhenylketonuriaAutosomal recessive Prevents breakdown of phenylalanine, delays in cognitive function 13retinoblastomaAutosomal dominant Tumors in retinal of young children 15Marfan syndrome Autosomal dominant Affects connective tissue leading to weakness of heart, blood vessels and skeleton

AUTOSOMAL INHERITANCE AUTOSOMAL INHERITANCE PATTERNS (Page 220) CHROMOSOM E NUMBER CONDITIONINHERITANC E PATTERN DESCRIPTION 15Tay-sachs disease Autosomal recessive Progressive destruction of nervous system, accumulation of lipids 18Niemann- Pick disease Autosomal recessive Brain and nervous system impairment due to accumulation of lipids 19Maply syrup urine disease Autosomal recessive Inability to break down three amino acids, leading to nerve degeneration

AUTOSOMAL INHERITANCE AUTOSOMAL INHERITANCE PATTERNS (Page 220) CHROMOSOME NUMBER CONDITIONINHERITANCE PATTERN DESCRIPTION 20Adenosine deaminase deficiency causing severe combined immunodeficiency disease Autosomal recessive Deficiency in enzyme adenosine deaminase resulting in minimal immune response and susceptibility to disease

AUTOSOMAL DOMINANCE INHERITANCE Autosomal dominant pedigrees are common when the child is not affected and both parents are - Parents are hetoerzygous

AUTOSOMAL DOMINANCE INHERITANCE HUNTINGTON DISEASE (autosomal dominance) - Affected: AA or Aa; Unaffected aa - Brain deteriorates over a period of 15 years - Symptoms: decreased muscle co-ordination, erratic body movements, personality changes, decline in mental abilities - Lethal, no cure

AUTOSOMAL DOMINANCE INHERITANCE HUNTINGTON DISEASE (autosomal dominance)

AUTOSOMAL DOMINANCE INHERITANCE HUNTINGTON DISEASE (autosomal dominance) Find the genotypes of each person

AUTOSOMAL DOMINANCE INHERITANCE HUNTINGTON DISEASE (autosomal dominance) Find the genotypes of each person

AUTOSOMAL RECESSIVE INHERITANCE Autosomal recessive inheritance is common when two unaffected parents can have an affected child - Parents are carriers

AUTOSOMAL RECESSIVE INHERITANCE CYSTIC FIBROSIS (autosomal recessive disorder) - Unaffected: Aa or A; Affected aa - Most common fatal genetic disorder affecting young Canadians - Defective protein disrupting movement of Cl- across cell membranes which disrupts movement of water across cell membranes - Results in thickened mucus that builds up in the organs of the body - Breathing and digestive problems - No cure

AUTOSOMAL RECESSIVE INHERITANCE CYSTIC FIBROSIS (autosomal recessive disorder)