Presentation on theme: "Karyotype A chart of chromosome pairs arranged by length and location of the centromere."— Presentation transcript:
1 KaryotypeA chart of chromosome pairs arranged by length and location of the centromere
2 How are karyotypes made? Somatic cells (remember these are body cells) in metaphase are grown and then dropped onto a slide bursting the nucleus.The chromosomes are photographed, paired up and arranged by size.
4 Sex ChromosomesThe sex of the individual can be determined by examining the sex chromosomes.XX is a femaleXY is a male
5 Karyotype Notation1. List the total number of chromosomes (46 is normal for humans)2. List the sex chromosomes.3. List any extra or missing chromosomes
6 What is the sex of this individual? XY = male46XYNotation:
7 And this one?Klinefelter syndromeNotation:47 XXY
8 Klinefelter syndromeKlinefelter's syndrome is a condition that occurs in men who have an extra X chromosome in most of their cells. The most common symptom is infertility.Scientists believe the XXY condition is one of the most common chromosome abnormalities in humans. About one of every 500 males has an extra X chromosome, but many don't have any symptoms.
10 KaryotypesKaryotypes are used to identify defects in the chromosomes like:Missing chromosomesMultiple chromosomes
11 Do you see a problem?Trisomy 2147 XY +21Notation:
12 Trisomy Trisomy: 3 copies of one chromosome instead of the normal 2. Nondisjunction: (junction means joined) a chromosome pair fails to separate during meiosisOne cell ends up with 3 copies of a chromosome
13 Trisomy 21 or Down Syndrome Down syndrome (DS), also called Trisomy 21, is a condition in which extra genetic material causes delays in the way a child develops, both mentally and physically. It affects about 1 in every 800 babies.The physical features and medical problems associated with Down syndrome can vary widely from child to child. While some kids with DS need a lot of medical attention, others lead healthy lives.
15 Where is the trisomy?Edwards syndromeNotation:47 XY +18
16 Edward SyndromeTrisomy 18 (also known as Trisomy E or Edward's Syndrome) is a genetic disorder caused by the presence of all or part of an extra 18th chromosome. It is named after John H. Edwards, who first described the syndrome in It is the second most common autosomal trisomy, after Down Syndrome, that carries to term.The incidence of the syndrome is estimated as one in 3,000 live births. The survival rate of Edwards Syndrome is very low. About 95% die in utero. Of liveborn infants, only 50% live to 2 months, and only 5–10% will survive their first year of life.
19 Patau syndromePatau syndrome, is a chromosomal abnormality, in which a patient has an additional chromosome 13 due to a nondisjunction of chromosomes during meiosis. The extra chromosome 13 disrupts the normal course of development, causing heart and kidney defects. Like all nondisjunction conditions (such as Down syndrome and Edwards syndrome), the risk of this syndrome in the offspring increases with maternal age at pregnancy. Patau syndrome affects approximately one in 25,000 live births.Median survival age for children with Patau syndrome is 2.5 days, with only one in 20 children surviving longer than 6 months. However, some children survive into their teens and seem to fare better than might be expected based on reports from those who die in the perinatal period. Reports of adults with Patau syndrome are rare.
23 Cri-du-chatCri du chat syndrome, also known as chromosome 5p deletion syndrome, is a rare genetic disorder due to a missing part of Chromosome 5. Its name is a French term (cat-cry or call of the cat) referring to the characteristic cat-like cry of affected children.The condition affects an estimated 1 in 20,000 to 50,000 live births, strikes all ethnicities, and is more common in females by a 4:3 ratioThe syndrome gets its name from the characteristic cry of affected infants, which is similar to that of a meowing kitten, due to problems with the larynx and nervous system
24 Cri-du-chat Other symptoms SyndactylyCleft PalateMicrocephaly