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Definition
| – alternate form of a gene |
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Definition
| connection holding sister chromatids together is broken and pulled apart. Kinetochore microtubules ahorten and chromosomes move to opposite poles. Polar microtubules lengthen moving poles further apart. |
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Definition
| Programmed cell death. Involves cell shrinkage, chromatin condensation, DNA degradation, Facilitated by capsases |
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Definition
| position spindle apparatus |
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Definition
| affect organisms response to the environment. |
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Term
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Definition
4 stages:
1) G1 – gap 1 – cell prepares to divide
2) S – synthesis – where DNA replication occurs – sister chromatids form
3) G2 - Gap 2 – checkpoint phase
4) Mitosis
Gap phases are important for checking replication errors and cancel or correct. This is where cancers attack. |
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Term
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Definition
| divides a cell into 2. Asexual – binary fission (prokaryotes), mitosis (eukaryotes). |
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Definition
| detect abnormalities like DNA breaks and stop cell cycle progress – eg. p53 tumor suppressor gene |
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Definition
| composed of DNA and chromosomal proteins (histones coiled with DNA and nucleosomes) found in rod-shaped bodies…chromosomes. |
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Term
| Cyclins / Cyclin dependant kinases |
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Definition
| advance a cell through cell cycle. CDKs actu upon cyclin and monitor success of different phases of cell division at checkpoints. |
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Definition
| code for proteins that perform most life functions. |
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Definition
| proteins for genome maintenance. If inactive, a cell is more likely to become and oncogene. |
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Definition
| – sperm and egg haploid cells. |
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Term
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Definition
| – fundamental units of genetic material / information |
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Term
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Definition
| – the study of inheritance from expression, transmission, and evolution of genes, to distribution of traits in families and populations at the DNA, cellular, biochemical, organism, and population levels. |
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Definition
| – 2 alleles occupying same locus. One is dominant, one is recessibe. |
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Definition
| – other member of a pair of chromosomes |
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Term
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Definition
| 2 alleles occupying the same locus. Are both dominant or recessive |
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Term
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Definition
| ~ 3bil. Bp., 23 homologous pairs of chromosomes, numbered largest to smallest, except 21 smaller than 22, b/c x and y are not homologous, the recessive traits ARE expressed, meaning males are more likely to inherit and express disease |
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Term
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Definition
| – attach to kinetochore of centromere of chromosomes. |
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Term
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Definition
| – specific site occupied by genes |
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Definition
| pairs of sister chromatids align themselves along the metaphase plate. Chromatids are attached to both poles via kinetochore microtubules. |
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Term
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Definition
| – Prophase, prometaphase, metaphase, anaphase, telophase |
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Definition
| affect the appearance of an organism |
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Term
| p53 tumor suppressor gene |
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Definition
| checkpoint gene, has DNA binding domain and transcriptional activation domain. Associated with 50% of cancers. |
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Definition
| affect function of organism |
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Definition
| push poles away from each other |
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Definition
| spindle fibres interact w/ sister chromatids, kinetochore microtubules from poles and attach. |
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Term
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Definition
| Nuclear envelope dissociates, centromeres separate to opposite poles, mitotic spindle apparatus formed composed of microtubules formed by rapid polymerization of tubulin proteins. |
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Definition
| - chromosomes reach poles and decondense, nuclear membranes reform, and cleavage furrow 2 genetically identical daughter cells. |
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Definition
| any characteristic an organism displays, controlled by genes. |
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Definition
| head of sperm cell, contains digestive enzymes with which to eat into the egg. |
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Definition
| end of prophase I. Nuclear membrane begins to fragment. |
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Term
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Definition
| oogenesis and spermatogenesis. Both require meiosis, timing is different. |
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Term
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Definition
| – morphologically different gametes produces (eg sperm and eggs) |
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Term
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Definition
| eukaryotic species that are morphologically similar |
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Term
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Definition
| condensation of chromosomes |
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Term
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Definition
| process that produces haploid cells from diploid cells. Begins after interphase and ivolves 2 successive divisions: meiosis I and II. Each are divided into prophase, prometaphase, anaphase, and telophase. |
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Term
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Definition
| pairs of sister chromatids are aligned in a double row rather than in a single row like mitosis. |
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Definition
| production of egg cells in ovaries. Production of oocytes starts 3 months prenatally. 400 mature into egg cells. Arrested in prophase I until female is sexually mature. When activiated, proceed to meiosis I. Division of meiosis I is asymmetric – secondary oocyte is large, and polar bodies are small. eneters meiosis II, arrested in Metaphase II . This is when it is released into the oviduct. If fertilized, meiosis II progresses to completion. ¼ cells produced become eggs. |
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Term
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Definition
| – chromatid data crosses over. Tetrad complex, aka bivalent chromosome. Can happen anywhere. |
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Term
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Definition
| – subdivided into Leptotena, zygotena, pachytena, diplotena, and diakinesis |
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Definition
| where x and y chromosomes pair up. If pair up beyond this region, genetic anomaly occurs. |
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Definition
| way of producing offspring. Fusion of gametes from different parents with reduced chromosomal numbers to form a genetically recombined offspring. |
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Definition
| begins at puberty. Diploid spermatogonial cells divide mitotically to produce 2 cells – 1 spermatogonial cell, 1 primary spermatocyte. The primary spermatocyte goes through meiosis 1 to form 2 haploid secondary spermatocytes. These then go through meiosis II to form 4 spermatoids which then mature. 1 spermatogonial cell produces 4 sperm cells and another spermatogonial cell…..takes 64 days. |
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Term
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Definition
| begins and synaptonemal complex forms (join up) |
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Term
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Definition
| Autosomal dominant trait, lethal in homozygous form. Risk of affection increases with age. |
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Term
| Autosomal dominant traits |
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Definition
| does not skip generations. Gender neutral. Homozygous dominants express it more intensly. |
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Term
| Autosomal recessive inheritance |
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Definition
| traits are not expressed in heterozygotes and often skip generations, gender equal, often found in inbreds. Eg. Albinos, Tay sachs, sickle cell anemia, cystic fibrosis, PKU |
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Term
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Definition
| 2 true type mutant lines produce wild type gene. Shows when 2 mutant lines have same phenotype caused by mutations in different genes. |
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Definition
| 1/25 humans carriers. Gene encodes CFTCR which regulates ion transport across cell membranes. Mutation causes abnormalities of pancreas, intesting, lungs, and sweat glands. |
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Term
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Definition
| individual plants differ in 2 traits. Ratio becomes 9:3:3:1 in F2 |
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Term
| Dominant pattern of inheritance |
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Definition
| predicts an individual will have inherited the gene from at least 1 affected parent., or is the result of a new mutation |
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Term
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Definition
| when a gene can mask the effects of another gene b/c of 2+ fn-ing proteins |
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Term
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Definition
| range of phenotypic variability of a genetic trait – eg Taysachs…..infantile vs adult form. |
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Term
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Definition
| eg modifies agouti to black in mice. |
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Definition
| 1:1 ratio of potential traits |
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Term
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Definition
| 3:1 ration dom/recessive phenotypes |
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Term
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Definition
| – 2+ different genes influence the outcome of a trait. |
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Term
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Definition
| – genotype of a group of closely linked alleles on a single chromosome |
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Term
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Definition
| dominant mutation of CAG trinucleotide repeat expansion. Variable expressivity = more CAG repeats = earlier expression of disease. Neurodegenerative. 50% chance of offspring acquiring disease. CAG is cleaved by capsase IX, and cleaved. Cleaved peptides are neurotoxic. |
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Term
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Definition
| mating of 2 individuals with different characteristics. Results in hybrids |
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Definition
| intermediate between corresponding homozygotes. Eg purple flowers |
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Term
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Definition
Mendel’s postulates
1) Organism contains 2 distinct hereditary features, 1 from each parent
2) 2 factors may be identical or not
3) If different, 1 dominant, 1 recessive
4) During gamete formation, paired factors segregate randomly so half of the gametes receive 1 factor, and half the other = Mendel’s law of segregation |
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Term
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Definition
| – during gamete formation, segregation of any pair of hereditary determinants is independent of the segregation of other pairs. = INDEPENDENT ASSORTMENT |
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Definition
| crosses only 2 variants of one trait at a time |
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Term
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Definition
| unaffected parents of an affected child must be heterozygous for the trait |
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Term
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Definition
| – freq. of expressing a trait. Environment can play a large role. Described at population level. At individual level, something is only ever expressed or not expressed. |
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Term
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Definition
| results from deficiency of phenylalanine hydroxylase which results in a feedback loop increasing levels up to 200x of phenylalanine. Triggers a conversion of phenylalalanine to phenylpyruvic acid which is neurotoxic = mental retardations. Maternal PKU – mother eats phenylalanine when preg, passes on toxic levels to fetus = perm. Ment. Retard. |
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Term
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Definition
| – 1 genotype results in more than 1 phenotype. |
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Term
| Recessive inheritance predictions |
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Definition
1) 2 heterozygotes will have ¼ homozygous offspring
2) 2 affected individuals will produce 100% affected offspring
3) Affected and unaffected will be all heterozygous.unaffected parents of an affected offspring must be heterozygous for the trait - obligate heterozygote |
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Term
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Definition
| Involves the production of abnormal haemoglobin. Controlled by 2 genes (HbA and HbS) if homozygous HbA, get malaria, homozygous HbS get sickle cell anemia. If heterozygous, neither! Eg of pleiotropy. |
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Term
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Definition
| involves single gene w/ 2 diff alleles that display dom/recess relationship. Deviations can involve lethal alleles, eg. the manx cat and the yellow agouti mice that can result in early embryonic death. |
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Term
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Definition
| 2 genes on the same chromosome |
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Term
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Definition
| – from deficiency of hexosaminidase A neurodegenerative disorder at 4-6 months.undergraded gangliosides accumulate in the brain. Elevated in Ashkenazic Jewish pop. |
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Term
| Temperature sensitive conditional allele |
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Definition
| enzyme encoded by this allele is functional only at low temperatures |
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Term
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Definition
| variety that produces the same traits over several generations |
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Term
| x-linked recessive inheritance |
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Definition
| esp for males b/c they are hemizygous. Female passes on trait to ½ of sons. Eg. haemophilia, Duchene muscular dystrophy. Affected male and unaffected female have no affected offspring. Females will be carriers. Affected female and unaffected male will have affected male offspring and carrier female offspring. |
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Term
| Angelman / happy puppet syndrome |
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Definition
| – metal retard. Jerky gait. Seaizures, absent speech, laughing, sleep disoirders. Eg. of genomic imprinting from maternal genes |
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Term
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Definition
| – amount of x-linked products is same for females and males |
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Term
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Definition
| inheritance pattern where a mod to a nuclear gene or chromosome alters gene expression in an organism. Exp. Not changed permanently over the course of many generations. |
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Term
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Definition
| level of proteins and enzymes encoded by x-linked genes between males and females is similar. Because of lyon’s hypothesis |
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Term
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Definition
| – differential expression of either maternal or paternal allele in some regions of the genome instead of both. Chromosomal deletion in this region results in abnormal development. Eg. differences in methylation between maternal and paternal DNA. May result in mutations. |
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Term
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Definition
| only 1 of x-chromosomes is functionally active. Iinactive 1 condensed to a barr body. Day 18 of embryonic devo. Inactivates at random. Eg. calico cats--mosaics |
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Term
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Definition
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Term
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Definition
| from x-inactivation……some x’s from mother, some from father. |
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Term
| Prader-Willis Syndrome (PWS) |
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Definition
| neonatal hypotonism, facial dysmorphism, excessive eating, developmental delay, hypogonadism. Eg of genomic imprinting from paternal genes. Cartman |
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Term
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Definition
| allele is dom in one sex but modified in other…eg baldness. Usually related to something like testosterone. |
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Term
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Definition
| trait only occurs in 1 of the 2 sexes |
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Term
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Definition
| a female inactivation of fnctnl allele. Eg. colourblindness. |
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Term
| x-chromosome inactiviation mechanism |
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Definition
• X-inactivation center (xic) has gene called XIST (x-inactive specific transcript)
• XIST encodes RNA molecule w/o open reading frame that binds to its own x-chromosome. Starts to condense
• XIST blocked by antisense RNA called TSIX, whose encoding gene is located next to XIST gene.
• Downstream of xic is the X-chromosome controlling element (Xce) region.
• Two Xces – strong and weak. Strong a bit more favoured to remain active.
• 3 stages to inactivation – initiation, spreading, maintenance.
• Once inactivation begins, it spreads in both directions along the chromosome until all inactivated. Some genes escape inactivation in pseudoautosomal region. |
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Term
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Definition
| – executed by DNA N-glycolases. Cleaves an abnormal base between the sugar and DNA. |
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Term
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Definition
| – enhances chances of survival |
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Term
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Definition
| – affect phenotype under a defined set of conditions. Eg. temp. sensitive coats. |
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Term
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Definition
| removal of amino group from cytosine base. Can be repaired, but it is shifty. Esp. for methylated cytosine bases. |
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Term
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Definition
| decreases likelihood of surviving |
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Term
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Definition
| 3 steps. (1) detection, (2) removal, (3) normal synthesis |
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Term
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Definition
| most common. Removal of a purine from DNA. |
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Term
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Definition
| addition or deletion of nucleotides in multiples of 1 or 2. |
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Term
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Definition
| – caused by an environmental agent. Eg depurination, deamination, tautomeric shift |
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Term
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Definition
| an amino change does occur. Can be neutral if new amino acid has a similar chemistry. Is either non-sense mutation of a frameshift mutation |
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Term
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Definition
| heritable change in genetic material. Provides allelic variations, which is the foundation for evolutionary change. More likely to be harmful. Leads to development of DNA repair pathways |
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Term
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Definition
| mutagen uv light, has less energy, can’t penetrate deeply into muscles. Causes formation of crosslinked thymine dimmers. Leads to mutations when replicated. |
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Term
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Definition
| changes a normal codon to a termination codon. |
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Term
| Nucleotide excision repair |
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Definition
| needs UurA, UurB, UurC, and UurD. These remove short segments of damaged DNA. DNA polymerase and ligase then finish up. |
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Term
| needs UurA, UurB, UurC, and UurD. These remove short segments of damaged DNA. DNA polymerase and ligase then finish up. |
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Definition
| change in a single base pair via base substitution can be a transition of a transversion, or involve insertion or deletion of short DNA sequences. |
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Term
| Removal step of DNA repair |
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Definition
| Base excision repair, nucleotide excision repair |
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Term
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Definition
| base substitutions that do not alter the amino acid sequence of the polypeptide. |
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Term
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Definition
| – result from abnormalities in cell process |
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Term
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Definition
| – temporary change in base structure. Must occur prior to DNA replication. Results in mis-base pairing (eg T binding with G instead of A) |
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Term
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Definition
| pyrimidine to pyrimidine (CT) or purine to purine conversion (GA) |
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Term
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Definition
| pyrimidine to purine mutation. |
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Term
| Trinucleotide repeat expansions |
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Definition
| addition of a codon set increasing from 1 generation to the next. Eg. huntington’s and fragile-x. |
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Term
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Definition
| alters organism’s phenotype. |
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Term
| Chromosomal changes and abnormalities that result in cancer |
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Definition
| – usually a change in number or structure. Usually detected by microscope examination. Euploidy, Aneuploidy, deletions, inversions, translocations |
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Term
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Definition
| – multiples of the basic chromosome set |
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Term
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Definition
| abnormal numbers of individual chromosomes |
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Term
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Definition
| – terminal, intercalary, deletion loop |
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Term
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Definition
| 2 breaks with 180º rotation. No loss or gain of material. Can be Paracentric (centromere outside inverted segment) or Pericentric (centromere inside inverted segment) |
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Term
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Definition
| exchange of material between 2 non-homologous chromosomes. Can be Reciprocal (material exchanged in both directions on any chromosome – arm ratio changes, but not chromosomal number), or robertsonian (fusion btwn 2 acrocentric chromosomes) special structure – translocational cross |
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Term
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Definition
| – btwn 9 and 22. reciprocal translocation, 22 takes on protoncogene. Causes leukemia |
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Term
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Definition
| 4 chromosomes in 1 config. |
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