Human Molecular Genetics IV. Genetics of common diseases/ Multifactorial genetics
Human Genetics
description
Transcript of Human Genetics
![Page 1: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/1.jpg)
Human Genetics
![Page 2: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/2.jpg)
Multiple Alleles
• There are more than two possible genes that can be inherited for a trait.
• Examples– Flower color– Blood type
![Page 3: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/3.jpg)
Sex-linked Traits
• Trait for which the gene is located on one of the sex chromosomes.
XHXH ~ female, normal
XHXh ~ female, normal carrier
XhXh ~ female, hemophiliac
XHY ~ male, normal
XhY ~ male, hemophiliac
![Page 4: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/4.jpg)
Pedigrees
• A family tree that shows how a particular trait is passed from parents to offspring.
• Be able to read and interpret
![Page 5: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/5.jpg)
Pedigree of a Sex-linked Trait
• Colorblindness is sex-linked.
• Blue box is colorblind
• White box is normal vision with two normal genes.
• Half blue/half white is a carrier with normal vision, but one abnormal gene.
![Page 6: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/6.jpg)
![Page 7: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/7.jpg)
Karyotypes
• Process in which cells undergoing mitosis are crushed, and their chromosomes paired up. This can reveal abnormalities as seen below.
Female – 2 X chromosomes
![Page 8: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/8.jpg)
Nondisjunction• The failure of
chromosomes to separate during anaphase I or II of meiosis.
• Can result in too many chromosomes (Down Syndrome) or not enough (Turner Syndrome)
![Page 9: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/9.jpg)
Autosomal Dominant Diseases
• If the abnormal gene is present, the person has the disease– Huntington’s Disease
![Page 10: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/10.jpg)
Huntington’s Disease
• Chromosome 4• HH or Hh• Nerve cells degenerate• Symptoms include: mood swings, irritability,
loss of memory, and uncontrolled movements• People of western European descent
![Page 11: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/11.jpg)
Autosomal Recessive disease
• Must have 2 abnormal forms of the gene for the disease to be present– Cystic Fibrosis– Tay Sachs– PKU (Phenylketonuria)– Sickle Cell Anemia
![Page 12: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/12.jpg)
Cystic Fibrosis
• Chromosome 7• cc• Causes think, sticky mucus to build up in the
lungs, digestive tract, and other areas of the body
• Mainly Caucasians
![Page 13: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/13.jpg)
Tay Sachs
• Chromosome 15• tt• Causes a buildup of a chemical
on the nerve cells• Babies lose or fail to gain
motor and mental skills• Paralysis usually occurs• Death at an early age• Jews of eastern European
descent and French-Canadians
![Page 14: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/14.jpg)
PKU
• Chromosome 12• pp • Born without the ability to break down
phenylalanine• Smaller than normal head, epilepsy, and
mental retardation may occur when undiagnosed
• Caucasians and east Asians
![Page 15: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/15.jpg)
Sickle Cell Anemia
• Chromosome 11• ss• Red blood cells form an abnormal crescent
shape• Pain; spleen, lung, and heart damage, and
anemia• People of African
descent
![Page 16: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/16.jpg)
Sex-linked Diseases
• Gene for the disease is carried on the sex-chromosome– Colorblindness– Hemophilia
![Page 17: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/17.jpg)
Colorblindness
• Carried on the X chromosome
• XbXb or XbY• Cannot distinguish
between colors• Affects all races and ethnic
groups
![Page 18: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/18.jpg)
Hemophilia
• Carried on the X chromosome
• XhXh or XhY• Blood does not clot
well because missing the gene that codes for a blood clotting protein
• Affects all races and ethnic groups
![Page 19: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/19.jpg)
Chromosomal Aneuploidy Diseases
• A disease caused by an abnormal number of chromosomes– Down Syndrome– Turner’s syndrome– Kleinfelter’s syndrome– XYY Male
![Page 20: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/20.jpg)
Down’s Syndrome
• Autosomal anueploidy• Trisomy (three
chromosomes at 21)• Mental retardation,
upward slant to the eyes, decreased muscle tone, and a variation of other symptoms
![Page 21: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/21.jpg)
Turner’s Syndrome
• Sex chromosome anueploidy
• Monosomy• Alters development in
females; shorter than average, infertile, extra skin on the neck, skeletal abnormalities, heart defects, and kidney problems
![Page 22: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/22.jpg)
Kleinfelter’s Syndrome
• Sex chromosome anueploidy
• Trisomy (XXY)• Armpit and facial hair,
enlarged breasts, tall stature, and abnormal body proportions
• Increased possibility of learning disorders
![Page 23: Human Genetics](https://reader035.fdocuments.in/reader035/viewer/2022062501/5681658d550346895dd8595f/html5/thumbnails/23.jpg)
XYY Male
• Sex chromosome anueploidy
• Trisomy (XYY)• Increased risk of
learning disabilities, delayed speech and language skills