* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Document
Oncogenomics wikipedia , lookup
Point mutation wikipedia , lookup
Genome evolution wikipedia , lookup
Dominance (genetics) wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
History of genetic engineering wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Ridge (biology) wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Gene expression programming wikipedia , lookup
Skewed X-inactivation wikipedia , lookup
Minimal genome wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Neocentromere wikipedia , lookup
Gene expression profiling wikipedia , lookup
Genomic imprinting wikipedia , lookup
Y chromosome wikipedia , lookup
Microevolution wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Designer baby wikipedia , lookup
Two copies of each autosomal gene affect phenotype (physical). • Mendel studied autosomal gene traits, like hair texture. Autosome – chromosome with genes not related to sex of organism (body cells) Karyotype The arrangement of all the chromosomes found in a cell. Includes: Autosomes: chromosome pairs 1-22 Sex Chromosomes: chromosome pair 23 Female = XX Male = X Y 23rd pair Female sex chromosomes XX FEMALE “Autosomes” MALE Sex Chromosomes (they determine male or female) Who determines the sex of the offspring? Father – he can provide an X or Y chromosome Egg X X XX XX X X Body Cell X XX XX XY XY X XY Body Cell Y Y Sperm 1female:1male – Carrier – has an allele for as trait or disease that is not expressed. – Carrier does not have disease symptoms but can pass it on to offspring. Dominant allele disorders are rare. Huntington’s disease is an example of a disease caused by a dominant allele. (dominant) • Genes on sex chromosomes are called sex-linked genes. . – Y chromosome - male characteristics . – X chromosome - genes affects many traits. Males can pass on X or Y Females only pass on X Sex-linked disorder: Color Blindness 1. Genetic disorder found on the sex chromosome X 2. Known as a “sex-linked” because its found on chromosome 23 3. Can’t distinguish between colors 4. More boys, than girls, are color blind…..WHY? Sex-linked disorder: Color Blindness XC XC Color blind Dad and Normal mother produces…. Two normal sons XC XC XC XC XC Y XC Y XC XC 2 “carrier” daughters (NOT color blind) XC Y XC XC XC XC XC Normal Dad and Carrier mother produces…. 1 color blind son, 1 normal son 1 “carrier” daughter, 1 normal daughter Y XC Y XC Y What is the only way to get a color-blind daughter?? Sex-linked disorder: Hemophila 1. Recessive genetic disorder found on the sex chromosome X 2. Disease in which blood doesn’t clot properly. Sex-linked disorder: Hemophila XH XH Affected dad and Normal Mother produces…. Two normal sons Xh XH Xh XH Xh Y XH Y XH 2 “carrier” daughters XH Y Xh Normal Father and Carrier Mother produces…. XH XH XH XH Xh 1 color blind son, 1 normal son 1 “carrier” daughter, 1 normal daughter Y XH Y Xh Y What cross will ALWAYS yield you 100% affected sons? • Males have an XY genotype. – All of a male’s sex-linked genes are expressed. – Males have no second copies of sex-linked genes – Y chromosome is much smaller • Females have an XX genotype. X chromosome inactivation -randomly “turns off” one X chromosome. Why are males more likely to than females to have genetic disorders? All sex-linked genes are expressed, even recessive. Females have a backup X chromosome. • Some traits are neither totally dominant nor totally recessive. • Incomplete dominance - when neither gene is totally dominant to the other - Heterozygous phenotype is intermediate between the two homozygous phenotypes – Example: White flowers and red flowers produce pink flowers Sickle Cell Anemia • Disease in which the body makes sickle-shaped red blood cells. Sickle-shaped cells don’t move easily through your blood vessels. They’re stiff and sticky and tend to form clumps and get stuck in the blood vessels •The disorder is found on chromosome 11. and is therefore not sex-linked. • The Oxygen carrying hemoglobin can not carry oxygen as efficiently and the odd-shaped cells can easily clot and break. Fatigue, pain, and organ failure due to lack of oxygen supply are common symptoms of sickle cell anemia. • It is common in the African community Actual blood cells Sickle Cell Anemia Codominance Practice • Genes for blood cells: • R = Round blood cells • R’ = Sickle Cells R R’ Genotypes for blood cells RR = normal blood R RR’ = some sickle cells, some normal cells R’R’ = has sickle cell anemia R’ RR RR’ RR’ R’R’ Complete the following crosses, Report the genotypes and phenotypes of the offspring R = round blood cell R’ = sickle cell R R’ = carrier Mixed Cells x Hybrid ---------- x ---------R’ R Round Blood Cells x Hybrid ---------- x ---------EXPECTED R R EXPECTED R’ R’ R’ R RESULTS 1 sickle cell anemia -------------------------- R’ R’ R R’ R R R’ R RR 2 mixed cells -------------------------1 normal cells -------------------------- R RR RR R’ Sickle Cell Anemia x Pure Round ---------- x ---------- R’ R’ R’ R’ R R’ R R’ R’ R’ R’ R EXPECTED RESULTS 1 sickle cell anemia -------------------------- 2 mixed cells -------------------------1 normal cells -------------------------- RESULTS 2-------------------------mixed cells 2-------------------------normal cells -------------------------- Round Blood Cells x Sickle ---------- x ---------- R’ R’ R’ R’ R’ R’ R’ R R’ R R’ R EXPECTED RESULTS 1-------------------------sickle cell anemia 2-------------------------mixed cells 1-------------------------normal cells Incomplete dominance Red White X There is a third color that exists in the heterozygous . type. It’s a mixture between the two homozygous types. Pink • Color blindness is a problem in which red or green look like shades of gray or other colors. • The gene is carried on the X chromosome and is a recessive trait. XCXC = normal female XCXc = female, normal vision (carrier) XCY = normal vision male XcY = color blind male XC XC Y Xc XCXC XCXc XCY XcY • Codominant - alleles will both be completely expressed. – Codominant alleles are neither dominant nor recessive. – The ABO blood types result from codominant alleles. Example – red and white flower produce a flower with BOTH colors • Many genes have more than two alleles. 1. Blood Type 4 different blood types • there are _________________________ Blood Type Genes Blood Type A A A or A O Blood Type B B B or B O Blood Type AB AB Blood Type O OO Which blood types are compatible for transfusion?? Yes or No ? O B A AB B Yes A No AB Yes A No Yes O AB A A B AB AB B AB A A B AA AB A O B AB BO O AO OO A B AB B O AO BO O AO BO AB BB O O A AO AO A AA O OO OO O AO A O AO OO Blood type statistics… • If there are 100 people in the room: 39 will be O+ 7 will be O34 will be A+ 6 will be A9 will be B+ 2 will be B3 will be AB+ and only 1 in 200 will be ABNote: The + and – is the presence (or absence) of a third antigen (Rh). • Polygenic traits are produced by two or more genes. Order of dominance: brown > green > blue. • Epistatic gene - can interfere with the expression of all other genes. Mice have 5 genes that control fur color. 2 genes for general color 1 for shading 1 for spots 1 epistatic gene for color that overrrules all other genes • Phenotype is a combination of genotype and environment. • The sex of sea turtles depends on both genes and the environment. Warm eggs develop into females • Height is an example of a phenotype strongly affected by the environmental factors such as early nutrition and health care. Gene linkage was explained through fruit flies. • Morgan found that linked traits are on the same chromosome. Traits can be inherited as a group. • Chromosomes, not genes, assort independently during meiosis. Wild type Mutant • Linked genes are not inherited together every time. • Chromosomes exchange homologous genes during meiosis. Linkage maps – map of location of genes on a chromosome. • The closer together two genes are, the more likely they will be inherited together. • Cross-over frequencies are related to distances between genes. • Cross-over frequencies can be converted into map units. – gene A and gene B cross over 6.0 percent of the time – gene B and gene C cross over 12.5 percent of the time – gene A and gene C cross over 18.5 percent of the time Human genetics follows the patterns seen in other organisms. • The basic principles of genetics are the same in all sexually reproducing organisms. – Inheritance of many human traits is complex. – Single-gene traits are important in understanding human genetics. Females can carry sex-linked genetic disorders. • Males (XY) express all of their sex linked genes. • Expression of the disorder depends on which parent carries the allele and the sex of the child. X chromosome carries about 1100 genes while the Y carries about 250 Pedigree - chart for tracing genes in a family. • Phenotypes are used to infer genotypes on a pedigree. • Autosomal genes show different patterns on a pedigree than sex-linked genes. Widow’s peak: W = widow’s peak w = non widow’s peak • If the phenotype is more common in males, the gene is likely sex-linked. Colorblindness: M = normal vision m = colorblindness Several methods help map human chromosomes. • Karyotype - a picture of all chromosomes in a cell. XY FEMALE “Autosomes” MALE Sex Chromosomes (they determine male or female) Amniocentesis A medical technique used to collect the chromosomes of a developing fetus. It is done by inserting a needle into the womb and gathering cells in the amniotic fluid. • Karyotypes can show changes in chromosomes. – deletion of part of a chromosome or loss of a chromosome – large changes in chromosomes – extra chromosomes or duplication of part of a chromosome