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Transcript of human karyotype
Karyotype Index What´s DNA? Human karyotype Genetic diseases composed of? the central dogma What is it? Groups Alleles characteristics What´s DNA
DNA is a structure which contains all the information necessary for the development of all the functions of your body. All DNA is stored in each cell in structures we call chromosomes. Human species has in total 46 chromosomes, which are grouped into 23 pairs, each pair consisting of one chromosome from our mother and one from our father. To duplicate all this information stored in the chromosomes and to make it usefull cells use a process we call central dogma. Central dogma of molecular Duplication Transcription Translation Human Karyotype Genetic Most genetic disorders are quite rare and affect one person in every several thousands or millions. Diseases Single gene disorder A single gene disorder is the result of a single mutated gene. There are estimated to be over 4000 human diseases caused by single gene defects. Single gene disorders can be passed on to subsequent generations in several ways. Definition A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Types Multiple gene disorder Depending on which type of chromosome is afected, they can be classified in Autosomal Sexual When the disease is related onto a no sexual chromosome Dominant Recesive Only one mutated copy of the gene will be necessary for a person to be affected by an autosomal dominant disorder. Each affected person usually has one affected parent. There is a 50% chance that a child will inherit the mutated gene. Conditions that are autosomal dominant sometimes have reduced penetrance, which means that although only one mutated copy is needed, not all individuals who inherit that mutation go on to develop the disease. Examples of this type of disorder are Huntington's disease Two copies of the gene must be mutated for a person to be affected by an autosomal recessive disorder. An affected person usually has unaffected parents who each carry a single copy of the mutated gene (and are referred to as carriers). Two unaffected people who each carry one copy of the mutated gene have a 25% chance with each pregnancy of having a child affected by the disorder. Examples of this type of disorder are cystic fibrosis x linked DOMINANT
X-linked dominant disorders are caused by mutations in genes on the X chromosome. Only a few disorders have this inheritance pattern, with a prime example being X-linked hypophosphatemic rickets. Males and females are both affected in these disorders, with males typically being more severely affected than females. Some X-linked dominant conditions such as Rett syndrome, incontinentia pigmenti type 2 and Aicardi syndrome are usually fatal in males either in utero or shortly after birth, and are therefore predominantly seen in females. Exceptions to this finding are extremely rare cases in which boys with Klinefelter syndrome (47,XXY) also inherit an X-linked dominant condition and exhibit symptoms more similar to those of a female in terms of disease severity RECEssIVE X-linked recessive conditions are also caused by mutations in genes on the X chromosome. Males are more frequently affected than females, and the chance of passing on the disorder differs between men and women. The sons of a man with an X-linked recessive disorder will not be affected, and his daughters will carry one copy of the mutated gene. A woman who is a carrier of an X-linked recessive disorder (XRXr) has a 50% chance of having sons who are affected and a 50% chance of having daughters who carry one copy of the mutated gene and are therefore carriers. Y linked Y-linked disorders are caused by mutations on the Y chromosome. Because males inherit a Y chromosome from their fathers, every son of an affected father will be affected. Because females inherit an X chromosome from their fathers, female offspring of affected fathers are never affected.
Since the Y chromosome is relatively small and contains very few genes, there are relatively few Y-linked disorders.Often the symptoms include infertility Genetic disorders may also be complex, multifactorial, or polygenic, meaning that they are likely associated with the effects of multiple genes in combination with lifestyle and environmental factors. Multifactorial disorders include heart disease and diabetes. Although complex disorders often cluster in families, they do not have a clear-cut pattern of inheritance. This makes it difficult to determine a person’s risk of inheriting or passing on these disorders. Complex disorders are also difficult to study and treat because the specific factors that cause most of these disorders have not yet been identified.
On a pedigree, polygenic diseases do tend to “run in families”, but the inheritance does not fit simple patterns as with Mendelian diseases. But this does not mean that the genes cannot eventually be located and studied. There is also a strong environmental component to many of them (e.g., blood pressure).
autoimmune diseases such as multiple sclerosis
cancers biology As the final step in the Central Dogma, DNA replication must occur in order to faithfully transmit genetic material to the progeny of any cell or organism. Duplication is carried out by a complex group of proteins called the replisome which consists of a helicase that unwinds the superhelix as well as the double-stranded DNA helix, and DNA polymerase and its associated proteins, which insert new nucleic in a sequence specific manner. This process typically takes place during S phase of the cell cycle. Duplication consists in replicating the DNA stored in the nucleus of a cell. It´s done during the synthesis phase of the life of a cell. Duplication is carried out by a complex group of proteins: DNA Polymerase: Enzyme Responsible for DNA synthesis. Helicase: Opens the helix (which causes strand separation) GROUP A
Chromosome 3 is the smallest of the whole set. Both arms have a similar amount of stripes. Chromosome number 1 is the biggest of the whole set. The short arm, the one that is closest to the centromere, usually has two stripes.
Chromosome 2 is submetacentric. Both arms are covered with stripes Chromosomes 1,2,3 (two pairs each) GROUP B Chromosomes 4 and 5,
submetacentrics Chromosome number 5 has only one stripe in its short arm, and in the middle of the big one it has lots of them.
Chromosome 4 can be distinguished because the largest arm presents various stripes. GROUP C Chromosomes from 6 to 12 plus the X chromosomes. They are submetacentrics Chromosome 6 is sometimes confused with those of group B. It has a short arm with a distal band between the centromere and that band is a zone of very weak staining. In the long arm shows several bands
The chromosome 9 stands very well as a band is quite large interstitial on the short arm and two very sharp bands in length.
Chromosome 7 is similar to the former has a distal band on the short arm of 6 but differs in that in the long arm has two bands very clear and defined. Chromosome 8 is the most difficult to distinguish, because depending on the stain, more specifically, its contrast, can appear on the long arm bands or not, the simplest is to leave it for last, when they have solved the other chromosomes the group. GROUP D Chromosome 13 has a band near the centromere and then two bands that sometimes appear together in the most distal but without being telomeric Chromosome 14 has two bands on the long arm, one near the centromere and one farthest from the same but not as distal as chromosome 13. The chromosome 15 is significant because it has a band around the middle of the arm. Furthermore, the proximal half of the arm appears even more dyed that the distal half. Group D (chromosomes 13, 14 and 15) acrocentric. human characteristics related to group A Chromosome 1: ASPM: a brain size determinant IRF6: gene for connective tissue formation GLC1A: gene for glaucoma F5: coagulation factor NGF: Nerve Growth Factor Chromosome 2: SLC40A1: solute carrier family COL5A2, COL4A4, COL4A3, COL3A1 are collagens ABCA12:ATP-binding cassette Chromosome 3: SCN5A: sodium channel, SOX2: transcription factor ZNF9: zinc finger protein 9 (a cellular retroviral nucleic acid binding protein) TMIE: transmembrane inner ear human characteristics related to group B Chromosome 4: IGJ: linker protein for immunoglobulin All genes related to chemokin are in this chromosome HCL2 (also called RHA or RHC): related to red hair ANK2: ankyrin 2, neuronal Chromosome 5: SMN: survival motor neuron Pikachurin: Responsible for the functioning of the ribbon synapses; allows the eye to track moving objects ERAP: endoplasmic reticulum aminopeptidase human characteristics related to group C Chromosome 6: plays a vital role in organ transplantation. contains over 100 genes related to the immune response PARK2: Parkinson disease PKHD1: kidney and hepatic disease Chromosome 7: DFNA5: Deafness TAS2R16: Taste receiver CCM2: cerebral cavernous malformation Chromosome 8: GULOP pseudogene: responsible for human inability to produce our own Vitamin C 8% of its genes are involved in brain development and function 16% are involved in cancer WRN: ATP-dependent helicase. Chromosome 9: TGFBR1: Receptor type I growth factor TMC1: transmembrane channel-like TSC1: Esclerosis tuberosa Chromosome 10: EGR2: early growth response GROUP E Group E (chromosomes 16, 17 and 18) submetacentric The submetacentric chromosome 16 is the largest of the small, usually appears quite clear or submitting any band on the long arm The submetacentric pair 17 is more than the previous one and has a band on the long arm. Chromosome 18 is the one with the smallest short arm of the group and has two bands on the long arm GROUP F Group F (chromosomes 19 and 20) metacentric Chromosome 20 has a band on the short arm The chromosome 19 presents no band in any of the chromosome arms to this resolution
GROUP G The chromosome 21 has a kidney-shaped appearance dark band which is absent in the 22 The chromosome 22 sometimes has a band around the middle of the long arm. Group G (chromosomes 21 and 22) acrocentric Transcription is the process of creating a complementary RNA copy of a sequence of DNA.
It has three main events.
Initiation - binding of RNA polymerase to double-stranded DNA; this step involves a transition to single-strandedness in the region of binding; RNA polymerase binds at a sequence of DNA called the Elongation - the covalent addition of nucleotides to the 3' end of the growing polynucleotide chain; this involves the development of a short stretch of DNA that is transiently single-stranded
Termination - the recognition of the transcription termination sequence and the release of RNA polymerase The synthesis of protein from RNA. Hereditary information is contained in the nucleotide sequence of DNA in a code.
ERCC6: excision repair cross-complementing rodent repair deficiency UROS: uroporphyrinogen III synthase Chromosome 11 HBB: hemoglobin DHCR7: 7-dehydrocholesterol reductase SBF2: SET binding factor 2 Chromosome 12 KCNA1: potassium voltage-gated channel KERA: keratocan, important to the transparency of the cornea. KRAS gene performs an essential function in normal tissue signaling Sexual Chromosomes . During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, antiparallel RNA strand. Amino acid chains are folded into helices, zigzags, and other shapes to form proteins and are sometimes associated with other amino acid chains. The coded information from DNA is copied faithfully during transcription into a form of RNA known as messenger RNA (mRNA), which is then translated into chains of amino acids.
THE END By: Juan Luis Ruiz-Tagle Jaime Alesanco Bibliography http://ghr.nlm.nih.gov/ http://en.wikipedia.org/ http://www.ucm.es/info/genetica/ X Chromosome Is one of the two sex-determining chromosomes in many animal species The X chromosome in humans spans more than 153 million base pairs (the building material of DNA) Females have two X chromosomes, whereas males have one X and one Y Y Chromosome The human Y chromosome is composed of about 60 million base pairs. It´s only present in males, which have an X and a Y chromosome Y chromosome is much smaller than the X one,
which makes this one to express all genes that have not pairs Chromosome 13: SLITRK1: mutation in this gene causes some cases of Tourette syndrome GJB2: gap junction protein SOX21; its disruption can lead to types of alopecia in mice. Chromosome 14: TSHR: thyroid stimulating hormone receptor COCH: coagulation factor PSEN1: presenilin 1 (Alzheimer disease) Chromosome 15: EYCL3 Eye color 3, BROWN EYCL2 Eye color 2,Determines the positionning of melanocytes on the iris MCPH4: microcephaly, Chromosome 16: Chromosome 17 Chromosome 18 It may explain about 1% of obesity cases Autism disease might be related from a mutation of this chromosome TP53: tumor suppressor protein S6K: Ribosomal protein RAI1: retinoic acid KC6: expressed in human cornea SMAD4: helps the nucleus to function properly Chromosome 19: HCL1: HAIR COLOR 1; BROWN HAIR COLOR EYCL1: EYE COLOR 1; EYE COLOR, GREEN/BLUE CACNA1A: Calcium channel Chromosome 20: BMP2: Bone Morphogenetic Protein VAMP (vesicle-associated membrane protein) DNAJC5: Cysteine string protein Chromosome 21 Chromosome 22 LAD: leukocyte adhesion RRP1B: ribosomal RNA processing PCNT: centrosomal pericentrin NEFH neurofilament SHANK3:connect neurotransmitter receptors to the actin cytoskeleton IGL: contains genes for the antibodies