DAY 2 Unit 3 Inheritance and Molecular Genetics 1

Inheritance of traits 46 chromosomes Organization – Nucleotides (ACTG) – Gene – Chromosome 2

Genes Dominant v. Recessive Alleles Homozygous v. Heterozygous for a trait Genotype v. Phenotype 3

Mendel Revisited Punnett Squares 4

Tay Sachs deadly disease of the nervous system passed down through families. body lacks hexosaminidase A, a protein that helps break down a chemical found in nerve tissue called gangliosides defective gene on chromosome 15chromosome Symptoms usually appear when the child is 3 to 6 months old. The disease tends to get worse very quickly, and the child usually dies by age 4 or 5. Symptoms include: delayed mental and social skills 5

Albinism defect of melanin production that results in little or no color (pigment) in the skin, hair, and eyes. The defects may be passed down through families. most severe form of albinism is called oculocutaneous albinism. People with this type of albinism have white or pink hair, skin, and iris color, as well as vision problems. 6

PKU Phenylketonuria (PKU) is a rare condition in which a baby is born without the ability to properly break down an amino acid called phenylalanine. Phenylalanine an essential amino acid Symptoms include: Delayed mental and social skills, Head size significantly below normal, Hyperactivity, Jerking movements of the arms or legs, Mental retardation Treatment: strict diet to limit Phenylalanine intake Treatment 7

Huntington inherited disease that causes the progressive breakdown (degeneration) of nerve cells in the brain. autosomal dominant disorder impact on a person's functional abilities and usually results in movement, thinking (cognitive) and psychiatric disorders. develop signs and symptoms in their 40s or 50s, but the onset of disease may be earlier or later in life 8

Huntington Disease continued Symptoms include:  Motor: Slow, uncoordinated fine movements Slow or abnormal eye movements Impaired gait, posture and balance Difficulty with the physical production of speech,  Cognitive: Difficulty planning, organizing and prioritizing tasks, Lack of impulse control that can result in outbursts, acting without thinking and sexual promiscuity, Slowness in processing thoughts or "finding" words,  Psychiatric: Social withdrawal Insomnia or excessive sleeping Fatigue, tiredness and loss of energy Feelings of worthlessness or guilt 9

Down Syndrome genetic disorder that causes lifelong developmental delays (mental, physical and social) and other problems. Continuum of severity Trisomy 21 (gamete production problem) 10

Alzheimer’s (familial) Familial Alzheimer's disease is an uncommon form of Alzheimer's disease that usually strikes earlier in life, defined as before the age of 65 (usually between 50 and 65 years of age, but can be as early as 15) autosomal dominant accounts for approximately half the cases of early-onset Alzheimer's disease. Familial AD requires the patient to have at least one first degree relative with a history of AD 11