19 dom missing protein that causes cholesterol

Unformatted text preview: te Americans Tay Sachs (Chr. 15, rec.) Missing enzyme resulting in build up of Missing fatty deposits in the brain, MR fatty 1/3300 E. Eur. Jews Phenylketonuria (PKU) (Chr. 12, rec.) Defective phenylalanine hydroxylase, Defective blocks conversion of phenylalanine to tyrosine, MR tyrosine, 1/10,000 White Americans Galactosemia (Chr.9, rec.) Deficiency in galactose-1-phosphate Deficiency uridyltransferase (GALT) leading to galactose build-up, MR galactose 1/80,000 Albinism (Chr. 11, rec.) Defective tyrosinase blocks conversion of Defective tyrosine to DOPA in the pathway to melanin in eyes, hair and skin in 1/10,000 in Northern Ireland Hypercholesterolemia (Chr. 19, dom.) Missing protein that causes cholesterol Missing buildup, early heart attacks buildup, 1/122 French Canadians Huntington disease (Chr. 4, dom.) Progress mental and neurological Damage and disorders by 40 1/25,000 White Americans BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 22 The X-Chromosome X chromosome sequenced chromosome and reported in Nature on March 17, 2005. 1098 genes. genes. Y chromosome sequenced chromosome and reported in Nature on June 19, 2003. 78 genes. June BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 23 X-Linked Inheritance Examples of X-Linked Disease in Humans Disease Anhidrotic ectodermal dysplasia (recessive) Duchenne muscular distrophy (recessive) Fragile-X Syndrome (recessive) Familial Hypophosatemia (dominant) Hemophilia A and B (recessive) Testicular Feminization (recessive) Frequency Symptom 7 in 10,000 No sweat glands 1 in 3000 or 4000 Muscular wastage in teenage years 1 in 1000 Mental retardation 1 in 20,000 vitamin D resistant rickets 1 in 10,000 1 in 65,000 male births Lack of blood clotting after trauma Lack of androgen receptors in males BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 24 Y-Linked Inheritance ­ There seem to be few genes that have been linked There to the human Y chromosome. Testis determining factor “TDF” and “Hairy ear” are two examples. “TDF” BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 25 Pedigree Analysis ­ Because humans can not be bred like fruit flies, Because mice and flowers, geneticists must resort to analyzing the descendants of the affected individual to determine the genetic basis of certain traits and diseases. ­ Over the years, geneticists and genetic counselors Over have developed symbols and a list of common characteristics of X-linked traits used for pedigree analysis. These symbols are shown on page 51 of your text and on handout accompanying this lecture. your BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BI...
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