Genetics

Clear your tables and be ready for el quizo! Bell-Ringer 1/6 Clear your tables and be ready for el quizo!

Today’s Goals Objective: Describe techniques such as chromosomal analysis (Karyotype) are used to study the genomes and disorders of organisms. Essential questions: How are genetic disorders identified through karyotypes of an organism’s chromosomes?

What are somethings you know that comes in pairs?

How about our chromosomes? Our chromosomes comes in pairs as well!

**Quiz corrections today-Friday! 1/23-Test on Friday! **Quiz corrections today-Friday! Have your Stamp sheet and Dihybrid Practice, monohybrid worksheet, station worksheets out! Stamp # 3 Monohybrid Practice Stamp # 4 Stations Stamp # 5 Dihybrid Practice

We have 23 PAIRS of chromosomes

What is chromosomal analysis (Karyotype)? Chromosomal analysis- Identifying chromosomes by their size and staining patterns in the order of decreasing length Used for identifying disorders in chromosomes

How to read a chromosomal analysis? Humans have 46 chromosomes, 23 chromosomes comes from Mom and the other 23 from Dad Chromosomes comes in 23 pairs

How to read a chromosomal analysis? Autosomal chromosomes- First 22 pairs of chromosomes codes for body proteins, body structures, etc… Sex chromosomes- Last 23rd pair chromosomes, represented by letters X and Y XX= female XY= Male The bands of chromosomes are cluster of Genes (DNA nucleotides)

Male or Female?

Male or Female?

How are chromosomes organized on chromosomal analysis (Karyotype)? Length of paired chromosomes- order from largest to smallest pair Placement of centromeres- the centromere of each pair has to match up Location and size of the “G” Bands (Dark bands)- G bands are clusters of Adenine (A) and Thymine (T)

Practice Question Observe the following karyotype. Describe how these chromosomes are arranged and paired up in a karyotype. How many total chromosomes? 3. Is this a male or female?

CHROMOSOMAL DISORDERS A KARYOTYPE CAN SHOW PROBLEMS ASSOCIATED WITH DISORDERS FOUND ON THE 46 CHROMOSOMES WE INHERIT This document maintained by Robert J. Huskey Last updated on November 10, 1998.

NONDISJUNCTION RESULT: ANUEPLOIDIES (WRONG # OF CHROMOSOMES) During Meiosis (gamete cells) the chromosomes failed to separate. Too many or too few chromosomes are sent to each sex cell. 45,47,48

IMPROPER # 0F CHROMOSOMES TRISOMY= HAVE THREE IN STEAD OF TWO MONOSOMY= MISSING ONE OUT OF THE PAIR. POLYPLOID= MORE THAN THREE NOTE: TWO = A PAIR A PAIR OF FLIP-FLOPS

Chromosomes A Chromosome is a bundle of DNA wrapped by proteins found in nucleus of Eukaryotes.

Chromosomal mutation Chromosomal mutation - changes in a part of, or the entire, chromosome. Result in: change in location of genes or number of genes

Types of Chromosomal Mutation Deletion Duplication Inversion Translocation

Deletion Loss of all or part of a chromosome.

Duplication Produces extra parts of a chromosome.

Inversion Reverses the direction of parts of chromosomes.

When part of one chromosome breaks off and attaches to another. Translocation When part of one chromosome breaks off and attaches to another.

WARNING: THE FOLLOWING SLIDES MAY BE UNSETTLING Viewers discretion may be advised…

PATAU’S SYNDROME TRISOMY #13 MENTAL DEFECTS HEAD DEFECTS EARLY DEATH  The extra copy of chromosome 13 in Patau syndrome causes severe neurological and heart defects which make it difficult for infants to survive. The exact incidence of Patau syndrome is not known, although it appears to affect females more than males, most likely because male fetuses do not survive until birth. Patau syndrome, like Down syndrome, is associated with increased age of the mother. It may affect individuals of all ethnic backgrounds. http://www.biology.iupui.edu/biocourses/N100/images/Trisomy13.gif

EDWARD’S SYNDROME TRISOMY #18 BODILY AND MENTAL DEFECTS EARLY DEATH Trisomy 18 is a somewhat common syndrome. It is three times more common in girls than boys. The syndrome occurs when there is extra material from chromosome 18. The extra material affects normal development. Symptoms Clenched hands Crossed legs Feet with a rounded bottom (rocker-bottom feet) Low birth weight Low-set ears Mental delay Poorly developed fingernails Small head (microcephaly) Small jaw (micrognathia) Undescended testicle Unusual shaped chest (pectus carinatum) http://www.larasig.com/sites/larasig.com/files/images/trisomy18_1.jpg

Cri-du-chat “Cry of the cat” Deletion of the short arm of #5 chromosome Bodily and mental defects Early death also known as 5p- (5p minus) syndrome, is a chromosomal condition that results when a piece of chromosome 5 is missing. Infants with this condition often have a high-pitched cry that sounds like that of a cat. The disorder is characterized by intellectual disability and delayed development, small head size (microcephaly), low birth weight, and weak muscle tone (hypotonia) in infancy. Affected individuals also have distinctive facial features, including widely set eyes (hypertelorism), low-set ears, a small jaw, and a rounded face. Some children with cri-du-chat syndrome are born with a heart defect. http://learn.genetics.utah.edu/content/disorders/whataregd/cdc/images/cri-du-chat_diagram.gif

KLINEFELTER’S SYNDROME XXY MALE WITH FEMININE APPEARANCE STERILE The most common symptom is infertility. Because they often don't make as much of the male hormone testosterone as other boys, teenagers with Klinefelter's syndrome may have less facial and body hair and may be less muscular than other boys. They may have trouble using language to express themselves. They may be shy and have trouble fitting in. http://medgen.genetics.utah.edu/photographs/diseases/high/cytog008.jpg

TURNER’S SYNDROME XO (MISSING 1 X-CHROMOSOME) SHORT FEMALE STERILE Girls who have it are short, and their ovaries don't work properly. Most are infertile. They are at risk for health difficulties such as high blood pressure, kidney problems, diabetes, cataracts, osteoporosis and thyroid problems. Other physical features typical of Turner syndrome are Short, "webbed" neck with folds of skin from tops of shoulders to sides of neck Low hairline in the back Low-set ears Swollen hands and feet http://bio3400.nicerweb.com/Locked/media/ch07/07_07b-Turner_syndrome.jpg

TRIPLE X X X X POSSIBLY NORMAL FEMALE MAY HAVE MENTAL AND REPRODUCTIVE PROBLEMS is characterized by the presence of an additional X chromosome in each of a female's cells. Although females with this condition may be taller than average, this chromosomal change typically causes no unusual physical features. Most females with triple X syndrome have normal sexual development and are able to conceive children. Triple X syndrome is associated with an increased risk of learning disabilities and delayed development of speech and language skills. Delayed development of motor skills (such as sitting and walking), weak muscle tone (hypotonia), and behavioral and emotional difficulties are also possible, but these characteristics vary widely among affected girls and women. Seizures or kidney abnormalities occur in about 10 percent of affected females. http://www.glogster.com/media/1/8/67/91/8679163.jpg

JACOB’S SYNDROME X Y Y SOME NORMAL MALE’S SOME MENTALLY ILL AND WILD TEMPER OFTEN VIOLENT CRIMINALS 47,XYY syndrome is associated with an increased risk of learning disabilities and delayed development of speech and language skills. Delayed development of motor skills (such as sitting and walking), weak muscle tone (hypotonia), hand tremors or other involuntary movements (motor tics), and behavioral and emotional difficulties are also possible. These characteristics vary widely among affected boys and men. A small percentage of males with 47,XYY syndrome are diagnosed with autistic spectrum disorders, which are developmental conditions that affect communication and social interaction. http://www.psd202.org/PEHS/departments/science/Severino/period_three_webpages/Jacobs_Syndrome/assets/karyotype.gif

DOWN SYNDROME TRISOMY #21 OR TRANSLOCATION 14/21 MENTAL RETARDATION Down syndrome is set of mental and physical symptoms that result from having an extra copy of chromosome 21. Even though people with Down syndrome may have some physical and mental features in common, symptoms of Down syndrome can range from mild to severe. Usually, mental development and physical development are slower in people with Down syndrome than in those without it. People with the syndrome may also have other health problems. They may be born with heart disease. They may have dementia. They may have hearing problems and problems with the intestines, eyes, thyroid and skeleton. The chance of having a baby with Down syndrome increases as a woman gets older. Down syndrome cannot be cured. However, many people with Down syndrome live productive lives well into adulthood. http://learn.genetics.utah.edu/content/disorders/whataregd/down/images/trisomy21_karyotype.jpg

Chromosomal Analysis/ Karyotype Station Lab Go to each station and use the information on the station card to answer the questions on your handout.