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28 Cards in this Set
- Front
- Back
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Mendel |
-Basic principles of inheritance and genetics -researched based on the phenotype of offspring from controlled breeding of large number of pea plants |
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Mendel's laws of segregation |
-Each parent has two copies of each trait, each parent passes on one copy -Caused by reduction division in meiosis -Exception: sex-linked traits (on X and Y chromosomes) ****MENDEL HAS NO IDEA ABOUT THE EXCEPTIONS BC NONE OF THE TRAITS HE OBSERVED WERE LINKED**** |
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Independent Assortment (also by Mendel) |
-Allele inherited for one trait doesn't influence the allele inherited for other traits -Caused by random orientation of homologous pairs and crossing over in meiosis -Exception: linked genes |
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Thomas Hunt Morgan |
-Fruit flies (Drosophila Melanogaster) -Many phenotypes -Controlled mating, rapid life cycle, and many offsprings -Identified non-Mendelian ratios -Sex-linked traits -Linked genes -Lethal alleles |
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Genotype |
-The alleles an organism has -Represented by a pair of letters (homo or hetero) |
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Phenotype |
-Characteristics of an organism -Often physical traits or appearance |
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Dominant Alleles |
-Stronger, same effect on genotype whether it is homozygous or heterozygous |
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Recessive Alleles |
Only has effect on the phenotype when homozygous |
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Codominant Alleles |
-In a heterozygous state, both alleles affect the phenotype -Written as capital letters with a superscript |
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Carrier |
Heterozygous, recessive gene is not shown in the phenotype |
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Test Cross |
Cross homozygous recessive gene with the gene suspected as carrier or with a dominant phenotype |
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Cystic Fibrosis |
-Normal, dominant allele codes for a membrane protein (CFTR) -Forms a chloride ion channel -Mucous |
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Huntington's Disease |
-Dominant Allele -Rare, symptoms occur later in life (often after reproduction, allele not eliminated) -Gene codes: normal allele has 10-28 CAGs -Huntington allele has 38-100+ CAGs -Lose ability to walk, reason, talk, and their personality changes -Death often 50-15 years before onset |
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Autosomes and Sex Chromosomes |
-Autosomes do not determine gender -Always found in homologous pairs in diploid organisms
-Sex Chromosomes determine gender -May not have homologous partner |
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Sex-linked genes |
-Genes that are on the X an Y-chromosomes do not follow Mendel's law of segregation |
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Mendel's law of segregation |
-A parent has 2 copies of the gene and passes on 1 **THIS LAW DOES NOT APPLY TO SEX CHROMOSOMES BC MALES HAVE 1 COPY OF EVERY GENE ON THE X AND Y-CHROMOSOMES. FEMALES HAVE 0 COPIES OF THE GENES ON THE Y-CHROMOSOME** |
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Inheritance of Y-chromosome genes: |
-Now only found in males -Only 1 y-chromosome per individual -If a trait is on the Y-chromosome: 50% of a father's children have it 100% of a father's sons have it 0% of a father's daughters have it |
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Red-Green Colorblindness |
-X-linked recessive gene -Recessive, x-linked gene -X^B: normal vision allele -X^b: color-blindness allele |
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Unlinked genes |
-Separate Chromosomes -Independent Assortment -Normal Punnett Grid Results |
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Linked genes |
-On same chromosomes -Close enough that crossing over separates them less than 50% of the time -Punnett grid results show more than parental type than recombinant |
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Recombinant |
-Alleles found in new combinations in offsprings than in parents -Occurs during random orientation of homologous chromosomes in Metaphase I -Crossing over prophase I separates genes on the same chromosomes |
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Radiation and Mutation |
-Exposure to high-energy radiation can cause mutations in DNA -X-rays, UV rays, gamma, beta, alpha (if consumed, etc. -New alleles formed -Harmful, may increase risk of cancer -Sometimes can be neutral and rarely helpful |
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Bombing of Hiroshima |
-An atomic bomb was detonated 0.6km above Hiroshima -Uncontrolled Chain Reaction -100,000+ people killed rapidly -Fires, shockwave, radiation poisoning -Increased risk of cancer, especially Leukemia -Chance of cancer increase with increase of radiation -Nagasaki also hit with atomic bomb |
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Chernobyl Nuclear Accident |
-Much more radioactive material than a bomb -Intended to supply energy through slow, controlled reaction -Failed test led to explosion and fire in a reactor -disaster level 7, highest possible (only other 7 is in Fukushima) -Radioactive fallout: Cesium-137, Cesium-134, Iodine-131, Strontium-90 |
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Chernobyl Accident Effects |
-4K+ cancer deaths, especially Leukemia and thyroid -local forest, horses, cattle died -bioaccumulation of radiation in fish -Evacuation of 350,000+ people -Current zone not safe for approx. 20K years -WIldlife may have higher mutation/cancer rates |
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Polygenic Traits |
-Multiple genes affect a trait -one trait influenced by 2+ genes -Polygenic traits usually are continuous variation -Single gene traits are categorical variation (variation and genetics) -Genetically influenced traits are also influenced by the environment |
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Penetrance |
-Possibilities of the alleles giving certain traits |
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Pleiotropy |
-1 gene affects multiple traits |
