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35 Cards in this Set
- Front
- Back
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Genome |
organisms complete set of DNA (all chromo, genes & DNA)
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Transcriptome |
collection of all transcripts (RNA) present in a given cell. Each cell distinctive transcriptome is end result of differential gene expression |
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Chromo in humans |
46 chromosomes (23 pairs) |
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Chromosome |
each chromo has a single piece of DNA, DNA packaged w/ histones. # genes per chromo varies not just b/c of length but also b/c of gene density on a chromo (some chromo have few/many genes) |
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Homologous chromo |
2 copies of each chromo (one from M one from D) you are born with homologous chromo-- upon fertilization embryo inherits 1/2 chromo form M & D |
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Ploidy |
# sets of copies (chromatids) of each chromo (46 total-- 23 M & 23 D) |
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Euploidy |
normal # chromo |
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Aneuploidy |
-abnormal # chromo -in embryos leads to early embryonic death at worst, or serious congenital defects -most prevalent genetic abnormality in humans, when including prenatal incidence |
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Diploid |
having 2 sets of copies of each chromo, having 2N # chromo N refers to a set of chromo, what is inherited from one parent all somatic cells are 2N |
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Haploid |
having 1 set of chromo 1N DNA amount that a gamete (sperm/egg) has |
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Autosomes |
refers all chromo except sex chromo (22 in humans). A human diploid somatic cell has 2 copies of each autosome = 44 autosomes total |
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Sex chromo |
X or Y somatic cells -- Female XX: 46, XX or 44 + XX Male XY: 46, XY or 44 + XY |
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Triploidy |
3 full sets of chromo 3N 66 (3 x 22) autosomes + 3 sex chromo (XXX, XXY, XYY) not viable (usually die during gestation or shortly after birth) |
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Turner Syndrome |
45, XO only viable monosomy ovary develops but have ovarian failure (require estrogen therapy to develop full secondary sex characteristics, menstrual irregularities) infertility, short stature, vast majority of spontaneous abortions |
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Klinefelter Syndrome |
XXY male testis develops, decreased testicular hormone function -Hypogonadism- low testosterone production, unable to make sperm, enlarged breasts, sparse facial hair, small testis |
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47, XXX |
ovary develops most have normal sexual development & fetility |
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47, XYY |
largely asymptomatic b/c few genes on Y chromo |
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Turner vs Kleinfelter Syndrome |
patients w/ Turner S have no Y chromo, one X chromo, they look like female patients w/ Kleinfelter S have one Y, two X chromo, they look like males |
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Y chromo rule (sex reversed patients) |
individuals who have short arm (but lost long arm) of Y chromo (results from chromo breakage) look male. individuals who have long arm (lost short arm) of Y chromo look female |
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SRY |
Sex determining region on Y chormo located on short arm of Y conveys info to make male gonads & external genitalia -XX mouse w/ SRY added, introduction of SRY into genome is enough to produce normal male looking phenotype, even though mouse appears male mouse does not make sperm & is infertile |
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Nondisjunction |
failure of chromo to undergo normal separation process that occurs w/ cell division. Most aneuplodies are not inherited genetic conditions & instead occurs as a result of nondisjuction |
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Chromatid |
a copy of chromo (2 copies of chromo that are held together at centromere) |
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C |
copy of chromo (chromatid) cell w/ 23 pairs of chromo is 2C |
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Sister chromatid |
arise in cells upon DNA replication |
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Mitosis |
1. DNA replication: diploid cells 2N 2C --> 2N, 4C (2 copies of each of 2 chromo = 4 copies) -Each specific chromo lines up w/ its own sister chromatid 2. Cell division: two cels w/ same DNA as "parental" cell 2N 2C |
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Meiosis |
2 divisons to produce haploid cells (each haploid human cell has one set of 23 chromo) 1. DNA replication 2. Meiosis I 3. Meiosis II |
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Meiosis step 1 |
1. DNA replication 2N2C --> 2N4C-chromatids of chromo 1 line up & chromo 22 line up = tetrad |
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Meiosis step 2 |
2. Meiosis I: 2N4C --> 1N2C + 1N2C-homologous chromo separated, sister chromatids still together, 1N haploid-- only one chromo, either one from M or one from D w/ 2 copies (2C) |
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Meiosis step 3 |
3. Meiosis II: 1N2C + 1 N2C --> 4x 1N2C (4 haploid, sister chromatid separate |
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Asexual reproduction |
duplicating or copying (essentially by mitosis) used by unicellular organisms Advantage: ease Disadvantage: no generation of genetic diversity |
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Sexual reproduction |
generation of a new genetically distinct individual through combination of genes from other individuals Disadvantage: expensive (effort to find mate) Advantage: generation of genetic diversity & a pop will have more diverse gene pool to adapt to new challenges |
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How sexual reproduction generates genetic diversity? |
1. by combining genes from 2 haploid cells from diff individuals to create a new, unique diploid individual 2. Tetrad line-up during meiosis: 2^3/2 = 4 combinations, 2^23/2 = 4x10^6 mix of M & D chromo 3. recombination during meiosis |
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Recombination |
occurs when 4 copies of chromo are lined up (before meiosis I), pieces of homologous chromo cross over & swap material, unique recombined chromo (hybrid of M & D) |
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Fertilization |
union of 2 gametes, each parent will have other chromo mixes in their gametes & chromo will vary |
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Advanced Maternal Age |
dramatic decline in egg quality >35 errors in meiosis, nondisjuction contributes to embryonic aneuploidy premature sister chromatid separation, homologous chromo fail to separate, sister chromatids fail to separate |
