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TOPIC : Genetics AIM : What is the gene chromosome theory? How do genetic disorders occur?. TOPIC: Genetics AIM : How do genetic disorders occur? DO NOW : Write the complimentary DNA strand that would be attached to the one below: C T A A C C G A G.
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TOPIC: GeneticsAIM: What is the gene chromosome theory? How do genetic disorders occur?
TOPIC:Genetics AIM: How do genetic disorders occur? DO NOW: Write the complimentary DNA strand that would be attached to the one below: C T A A C C G A G
Chromosomes & Genes… • The human DNA code is made up of about three thousand million A,T, C, and Gs on each side of the DNA strand. • If one were to recite the ATCG sequence in one's DNA which is 3 billion long and would utter at a rate of 100 ATCG sequences per minute without taking a break for sleeping, eating or drinking, one would speak for 57 long years.
Sex chromosomes 2 of 46 in each cell
X & Y • Eggs = X • Sperm = X or Y
XX = female • XY = male
Male chromosomes Female chromosomes
inherited diseases Genetic disorders Caused by genetic mistake Caused by mutations
mutation Change in gene or chromosome new trait
Duplication Deletion
Examples: 1. Addition: GTACA GTGCA 2. Insertion: ATG GTC AAT GGT C 3. Deletion: ATG GTC TCA AGG TCT CA
Nondisjunction = Chromosomes don’t separate properly during meiosis
RESULT: some cells have too many, some cells have too little
Harmful Mutations May cause various diseases & disorders
Helpful mutations Cause desirable traits Examples:
Potatoes= • Resistant to disease • Look and taste better
Bacteria = • Become more resistant to antibiotics that kill them
Bardet-Biedl Syndrome is a rare genetic disorder that affects many parts of the body. Only about 1 in 100,000 children have the disease, but those who do have it have multiple disorders in development throughout their bodies.
A kitten named Cy was born with a defect called holoprosencephaly. Animals born with holoprosencephaly are born with one eye and an unformed brain. Little Cy, adorable despite his deformity, sadly lived less than twenty-four hours after his birth.
A piglet owned by Llu Shuping, a pig farmer in Northwest China, has one head, two mouths, two noses, and three eyes. In China the little misfit is a television celebrity.
A genetic mutation has left this small kitten born in Perth, WI with two complete faces. Despite its deformities it is an affectionate kitten that constantly purrs with happiness.
The two-headed calf born in Iowa, US in April 1998 had four eyes and three ears and was appropriately named Reflections.
Two-headed python One-eyed frog
Three-legged duck Five-legged lamb
Venus Fly Trap with 2 traps Frog With Mutation
Left: A normal fruit fly Right: A fruit fly with its legs growing out of its head. This is a mutation caused by radiation.
1. Sickle cell anemia Blood disorder Caused by mutation Red blood cells change shape
Cannot obtain enough oxygen • Clump together and clog up blood vessels
2. Down Syndrome Caused by NONDISJUNCTION Extra copy of chromosome 21 Trisomy 21
Down syndrome (DS) causes delays in the way a child develops, and often leads to mental retardation, which means they may have trouble learning. It affects 1 in every 800 babies born. You have probably seen people who have DS. They have certain physical features, such as a flatter face & upward slanting eyes. It's important to note, though, that not all people with DS look alike or have all these features. They may have medical problems such as heart defects. Kids with DS can go to regular schools, make friends, enjoy life, and get jobs when they're older. DS affects kids' abilities in different ways. Kids with DS can and do learn, and are capable of developing skills throughout their lives. They simply reach goals at a different pace. Kids with DS have a wide range of abilities, and there's no way to tell at birth what they will be capable of as they grow up.
How can genetic disorders be detected?
1. AMNIOCENTESIS = Long needle removes amniotic fluid Fetal cells are tested
2. KARYOTYPE = Picture of all chromosomes in a cell