* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download X-linked genes
Point mutation wikipedia , lookup
Minimal genome wikipedia , lookup
Ridge (biology) wikipedia , lookup
Neuronal ceroid lipofuscinosis wikipedia , lookup
Saethre–Chotzen syndrome wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Public health genomics wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Dominance (genetics) wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
Gene expression profiling wikipedia , lookup
Gene expression programming wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Genomic imprinting wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Microevolution wikipedia , lookup
Designer baby wikipedia , lookup
Neocentromere wikipedia , lookup
Skewed X-inactivation wikipedia , lookup
Y chromosome wikipedia , lookup
X-linked traits Modes of Inheritance Autosomal Inheritance – Dominant vs. Recessive X-linked Inheritance – Genes only on X chromosome – Dominant vs. Recessive Codominance or Incomplete Dominance Cytoplasmic or Maternal Inheritance Sex Determination Pairs of chromosomes match Sex chromosomes don’t always match – X and Y – Females: X and X chromosome – Males: X and Y chromosome Cannot live without X chromosome – Y chromosome determines males Females are XX Possible gametes: all eggs will have one X chromosome X X X X X X Males are XY Half of male gametes will have one X chromosome Half of male gametes will have one Y chromosome X Y Y X X Y Punnett squares predict sex of offspring Genotype: 1XX:1XY phenotype: 1 female:1 male X-linked traits X is a sex chromosome It also has hundreds of genes – Very few have to do with gender Y does not have many of these genes – Very small chromosome – “sex determining” gene – “male fertility” genes http://www.uni.uiuc.edu/~dstone/XY.jpg History of X-linked genes Thomas Hunt Morgan @Columbia University in 1910 – Two students: Alfred Strutevant & Calvin Bridges Found white eye male fly(mutant) Normal(red eyes) They noted something weird… Mated white eyed male w/ red eyed female(normal) F1 all had red eyes F2 had 3:1 ratio Only males had white eyes Why? x Male Female Male http://www.nature.com/genomics/images/drosophila_200.jpg More research Morgan did find a white eyed female Cross with red-eyed female All the male offspring had white eyes!!! What was going on? Explanation Gene for eye color is found on X chromosome – Eye color gene is on different chromosomes in humans Gene not found on Y chromosome – So males only have allele of that gene These genes called Xlinked traits or Xlinked genes Color Blindness: X-linked Inheritance B: dominant normal b:recessive color blind allele Father only has one X chromosome to contribute Mom gives all normal genes All offspring are normal But all females are now carriers – Seem normal, but carry disease allele – Carry the hidden color blind gene – Create a punnett with a carrier as a mother X-linked Diseases Certain genes linked to diseases “+” means wildtype – Stands for normal gene – Found in “wild” populations “M or m” stands for mutation that causes disease – M= means mutations is dominant over wildtype – M= means mutations is recessive to wildtype M>+>m Examples of X-linked diseases Dominant X-linked disease (XM) – Rett’s syndrome – Vitamind D resistance Recessive X-linked disease (Xm) – – – – – Infantile spasm syndrome Duchenne Muscular Dystrophy Hemophilia A and hemophila B Two types of autistic disorders Color blindness Color Blindness Lack to see certain colors well Hard to distinguish them from other colors Red/Green Color Deficiency: most common – 99% of color deficiencies Blue/Yellow Deficiency: very rare – Very rare and way to test Seeing only gray is extremely rare In 8-12% of European males 0.5% of females 2 types of cells in eye Rod cells – Supersensitive in dim light – Lets you see at night – Doesn’t see in color Cones – Sees in bright light – Distinguishes color One absorbs red, green, and blue Color Blindness Red and green cones impaired or don’t work at all Can’t see red or green or see it differently than normal Ready to see colors? Previous Answer:25 What about this one? Previous Answer:29 What about this one? Previous Answer:45 What about this one? Previous Answer:56 And this one? Previous Answer:6 This one? Previous Answer:8 This one? That was a hard one. Normal:5 Color blind may see 2