Sex-Linked+Traits

Jason,Tyler, Boone

= Sex Linked Traits Information = Sex Chromosomes are the 23rd Pair of chromosomes. Women have two X chromosomes. Males have an X and a Y chromosome. Women pass down one of the X chromosomes and males pass on either an X or a Y to their offspring. If the offspring is a male the father passed his Y chromosome and if it is a girl the father passed down an X chromosome.

Men only inherit Y-linked traits, while both men and women inherit X-linked traits. Many women who carry X-linked recessive traits are just carriers because the other X masks the recessive trait. These traits are not shown in their phenotypes. Men who have an X-linked recessive trait are going to show that trait in their phenotype.

There are around 1,098 different X-linked genes. Many of these do not show up in a woman’s phenotype because the other chromosome covers it up. Many of the genes that don’t control the sex of a human are responsible for conditions such a hemophilia, muscular dystrophy, and red-green color blindness.

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= Hemophilia = Hemophilia is a disease that affects the clotting of the blood. Hemophilia is a sex linked disease. 1/10,000 males get it and 1/100,000,000 females get it so obviously its more likely that a male will get it other than a female.

There are 2 different types of hemophilia. Hemophilia A is the most common type of hemophilia. Some symptoms of hemophilia A are:

Hemophilia A is 7 times more likely to occur than Hemophilia B. Male babies are 50% more likely to get the disease than female babies. Hemophilia B is less common than Hemophilia A and have some different symptoms such as
 * Bleeding into joints, with associated pain and swelling
 * Blood in the urine or stool
 * Bruising
 * Gastrointestinal tract and urinary tract hemorrhage
 * Prolonged bleeding from cuts, tooth extraction, and surgery
 * Spontaneous bleeding
 * Blood in urine or stool
 * Extensive Bruising
 * Excessive bleeding following circumcision
 * Gastrointestinal tract and urinary tract hemorrhage
 * Nosebleeds Often
 * Prolonged bleeding from cuts, Tooth extraction, and surgery

(Hemophilia)

Queen Victoria of England was a carrier of the sex linked disorder hemophilia. She passed it on to one of her four sons and at least two of her five daughters. Her daughters were only carriers but her son Leopold died at the young age of thirty. The two daughters that were carriers spread the disease when they married into other European Royal Families. By the early 20th century ten descendants had hemophilia. Color blindness is another sex linked trait. Color blindness occurs when there is a problem with the color-sensing materials (pigments) in certain nerve cells of the eye.

= Becker’s Muscular Dystrophy = Becker’s Muscular Dystrophy, which is named after the German doctor Peter Emil Becker, is one form of a sex-linked inherited disorder. It is caused by mutations in the dystrophin gene, which results in the muscle cell membrane not being stable enough. This disorder, also called BMD, is passed on with an X-linked recessive inheritance pattern. This means that the gene controlling BMD is located on the X chromosome of the 23rd pair of chromosomes, or sex chromosomes, of humans. This disorder is rare, only affecting 3 to 6 in 100,000 male births, but is even rarer to have a fully affected female. Since BMD is passed on with a recessive X gene, females who get it from their fathers are usually just carriers because it will be covered up by a dominant unaffected X gene from their mother.

BMD is a rare disorder, but the symptoms can be very disabling and even fatal. Symptoms usually occur in men from ages eight to twenty-five. Affected people most commonly experience progressive muscle weakness and loss of muscle mass. They can have enlarged calves, difficulty breathing, and frequent falls. Some of the more serious symptoms include heart disease, mental impairment, and muscle and skeletal deformities. Because of its progressive onset, symptoms usually worsen as the person ages and until death.

Because BMD is not present right from birth and it is such a rare disease, it is very hard to diagnose. There is currently no treatment known to cure BMD, but just regular physical activity can improve an affected person’s condition and lengthen their life span. Since many problems during the onset of BMD are caused by loss of proteins, steroids and dietary changes have helped patients with muscle loss and mobility. The prognosis for affected people usually isn’t good though. Many people have trouble climbing stairs by age twenty and even though they may not be able to live a full life, lifespan is usually well into middle age.

(Beckers Muscular Dystrophy)

Links [|Sex Linked Activity] - It is a power point where it tells about sex-linked traits, and pictures of family trees with sex-linked traits. It also tells about the English Royalty who had hemophilia. [|Sex-Linked Traits Games, Quizzes, Learning] - This a link to Quizzlet.com. Has games, quizzes, documents, and sounds to help further yor learning and understanding of Sex-Linked Traits. Hemophilia Information Page- Tells about how people get hemophilia, the signs of hemophelia, and how it is treated.- Isaac []- Hemophilia A vs. Hemophilia B: Rebecca Pulse []- Dent's Disease Symptoms and Info: Rebecca Pulse []- Cody Bunger, 5 Question Quiz. Works Cited

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