* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Genetics & Inheritance - Parma City School District
Gene therapy of the human retina wikipedia , lookup
Cell-free fetal DNA wikipedia , lookup
Population genetics wikipedia , lookup
Ridge (biology) wikipedia , lookup
Polymorphism (biology) wikipedia , lookup
Epigenetics of diabetes Type 2 wikipedia , lookup
Point mutation wikipedia , lookup
Transgenerational epigenetic inheritance wikipedia , lookup
Medical genetics wikipedia , lookup
Gene desert wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Gene therapy wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Public health genomics wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Genetic engineering wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Genome evolution wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
Skewed X-inactivation wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
History of genetic engineering wikipedia , lookup
Gene expression profiling wikipedia , lookup
Dominance (genetics) wikipedia , lookup
Genomic imprinting wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Gene expression programming wikipedia , lookup
Neocentromere wikipedia , lookup
Y chromosome wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Genome (book) wikipedia , lookup
Microevolution wikipedia , lookup
X-inactivation wikipedia , lookup
Genetics & Inheritance The Chromosome Theory of Inheritance Chromosome Theory of Inheritance: • Genes that code for various traits are found on chromosomes which are made of DNA and found in the nucleus of each cell Thomas Hunt Morgan (1910): Studies Drosophilia melanogaster ;common fruit fly Discovered the gene for eye color and wing size were both located on the same chromosome (X) = Linkage Linkage = genes located on the same chromosome The closer the genes are on the chromosome, the greater the likelihood of crossing over The Law of Independent Assortment does not apply to linked genes! Gene Linkage Barbara McClintock & Harriet Creighton (1950): Studied Zea mays ; corn Looked at chromosome #9 They noticed that 2 copies of it were different sizes Conclusion = Crossing Over had occurred, an abnormal event caused a piece of another chromosome to attach itself to one of the copies of chromosome #9 Crossing Over disrupts normal Linkage Groups! Human Chromosomes Chromosomes: Humans have 46 individual chromosomes in every cell of the body except the sex cells 22 pairs = Autosomes (regular, information carrying chromosomes) 1 pair = Sex Chromosomes, determines gender (XX = female, XY = male) Which Parent determines the sex of the child? MODES OF INHERITANCE Different ways of inheriting genetic traits 1. Complete Dominance: dominant allele completely masks out the recessive trait (AA, Aa) Autosomal Dominant = trait carried on an autosome by a dominant gene (A) Autosomal recessive = trait carried by a recessive allele (aa) Example: flower color in pea plants P = Purple, p = white MODES OF INHERITANCE 2. Incomplete Dominance: One allele of a gene pair is not fully dominant over the other; being heterozygous produces an intermediate form, no masking occurs (AA, Aa, aa) Example: Flower color in snapdragons RR = red, rr = white, Rr = pink MODES OF INHERITANCE 3. Codominance: both alleles express themselves when heterozygous (Blood types A, AB, B, O). There is no true recessive trait. AB Blood type is an example of Codominance = Both alleles in the heterozygous form (IAIB ) end up expressing themselves equally. Both traits show up in the phenotype. Example: coat color in horses RR = red , WW = White , RW = roan (RR = red , R’R’ = White , R R’ = roan) RR x WW RW x RW MODES OF INHERITANCE Polygenic Traits: trait is controlled by more than one pair of genes (Eye color, Skin color, Human Height). This usually results in continuous variation. Polygenic inheritance is considered the opposite of Pleiotropy. 4. 5. Pleiotropy = when a single gene has more than one phenotypic expression. Example: Sickle Cell Anemia = misshapen red blood cells ultimately causes other problems such as anemia, pneumonia, heart & kidney failure, bone abnormalities, and impaired mental functioning. MODES OF INHERITANCE 6. Epistasis = one gene affects the phenotypic expression of a second gene. (Skin pigmentation) One gene codes for color, the other codes for the amount of pigment. MODES OF INHERITANCE 7. Multiple Alleles: a gene having more than two alleles (Blood types) PHENOTYPES A B * AB O % of Population 39% 12% 4% 45% GENOTYPES IAIA , IAIi IBIB , IBIi IAIB IiIi Blood Types Discovered in 1900 by Dr. Karl Landsteiner Based on the presence or absence of specific agglutinogens (clotting factors) on the surface of red blood cells (RBC’s = Erythrocytes) For example: a person with blood type A posseses A-antigens and Anti-B antibodies The blood will clot if a foreign Antigen is present Donor vs. Recipient • Universal Donor = Blood type O ; contains no A or B antigens No Clotting reaction Universal Recipient = Blood type AB ; contains both A & B antigens Will recognize antigens from any blood type Rh Factor Rh Factor = (Rhesus monkey) You either have it (+) or you don’t (-) Sensitization can occur by: – .)Rh+ blood transfused into Rh- person – .)Rh- mother carries a fetus who is Rh+ IAIA x IBIB IAIix IBIi MODES OF INHERITANCE 8. Sex-Linked Inheritance: trait carried on the sex chromosomes; usually the X (XX = female; XY = male) X-Linked Recessive = Xa (Colorblindness, Hemophilia) X-Linked Dominant = XA; Y-Linked (Rare) Carrier = person not affected by the trait but can pass it on to offspring = XA Xa Only females can be carriers for sexlinked traits because if a male has the gene, he will also exhibit the trait! MODES OF INHERITANCE X – inactivation: one of the two X chromosomes in a female does not uncoil during embryonic development. The chromosome that remains coiled is called a Barr Body and contains genes that will not get expressed. This could cause a sex-linked trait to affect a female that would normally be only a carrier. 9. MODES OF INHERITANCE 10. Sex-Influenced Traits: expressed in both sexes, but they are expressed differently (Pattern Baldness) B= Normal; b= Bald female (bb) = bald; male (bb or Bb) =bald BB x Bb Bb x Bb MODES OF INHERITANCE 11. Sex-Limited Traits: autosomal traits expressed in only one sex (Lion’s mane) MODES OF INHERITANCE • 12. Dihybrid Crosses: follow 2 traits at a time (AaBb) Example: A = purple flowers, a = white B = Tall, b = short If you cross two parents, where the father is AABB and the mother is aabb: the possible gametes are AB x ab. This can be determined using the F.O.I.L method. Dihybrid Crosses F = first O = outside I = inside L = last = 100% AaBb AABB x aabb Results --> RrYy x RrYy GENETIC DISORDERS Disorders or diseases related to a persons genes or chromosomes; inherited in the same ways as other traits. 2 Mechanisms exist: Genetic Disorders 1. Inherited on Genes: inherited as a trait (Autosomal, sex-linked, sex influenced, etc...) colorblindness hemophilia “bleeder’s disease” muscular dystrophy albinism Progeria Genetic Disorders 2. Chromosome Abnormalities: not caused by a gene A.) Extra or Missing Chromosomes. Aneuploidy = abnormal chromosome number – Non-Disjunction = failure of chromosome pairs to separate properly during meiosis, end up with daughter cells having either too many or not enough chromosomes in them. Ex. Down Syndrome “Trisomy 21” Genetic Disorders B.) Mutated Chromosome = damaged DNA, genes located in that section are damaged Deletion: missing gene or piece of chromosome Duplication: extra piece, genes duplicated Translocation: gene switches chromosomes Inversion: fragment of gene gets turned around SCREENING FOR DISORDERS 1. Karyotyping = genetic map of all the chromosomes that an organism possesses 2. Amniocentesis = test done before birth, take sample of amniotic fluid (C.V.S.) 3. Genetic Counseling = determine family medical history THE END!!