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| During development, these genes organize the principle axes of the body. They make structures develop in the appropriate places. They are very similar in many organisms and are well-characterized. |
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Definition
| Identify genes and mechanisms of diseases. Wanted to understand our underlying biology. 20,000 genes found. |
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| Single gene mutations that are phenotypically unseen. Shows that there is redundancy in our genetic code. |
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Definition
Single gene mutations that cause a phenotypic change. These can be:
1. Missense
2. Nonsense
3. Frameshift |
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Definition
| Mutations that produce a change in a single amino acid |
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Definition
| Changes that produce one of the three stop codons in the mRNA, causing premature termination |
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Definition
| A base is added or deleted from the genetic code (not in a multiple of three), causing the reading frame to change. This causes changes in many codons. |
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Term
| (Cause of) Sickle Cell Disease |
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Definition
| A missense mutation (a single gene mutation) in the beta hemoglobin switches a valine for a glutamic acid. |
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Definition
| As you go from generation to generation there is increased severity and a younger age of onset. |
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Definition
| A genetically normal individual who has a mutation in their germline carries a premutation. |
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Definition
| The methylation of a gene -- whether it has methyl groups attached at to histones and CG islands -- affects the gene expression. |
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| A mixture of genetically distinct cell populations/segmental gene expressions. Examples include NF1, Turner syndrome, and cancer. |
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Definition
| Parts strip away from the placenta and constrict parts of the paper, causing constriction rings. |
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Definition
| One of Mendel’s laws. Alleles come in pairs. When gametes are made, each gamete receives one of the pair. |
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Definition
| One of Mendel’s laws. Genes separate independently of one another. We now know an important exception to this is linkage. |
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Definition
| Different mutations in the same place (different alleles in the same locus) can cause the same abnormal phenotype. An example of this is cystic fibrosis. |
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Definition
| Mutations at two or more loci can cause similar phenotypes. Examples include RP -- there are 20 chromosomal regions that can be mutated -- or autosomal dominant breast cancer (BRCA1 and 2). Another example is polycystic kidney disease. |
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Definition
| A single mutation can cause multiple different phenotypic effects throughout the body. An example of this is Marfan’s syndrome -- one gene causes cardiovascular symptoms (aortic root dilation, mitral valve prolapse), musculoskeletal changes (tall stature, long fingers, pectus deformities), and ocular changes (lens dislocation). |
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Definition
| The proportion of individuals with a particular genotype that will express the phenotype (how many people with the gene will show the gene). 100% of people having the phenotype when they have the genotype is 100% penetrance. Examples of incomplete penetrance are split hand/foot malformations, hemochromatosis, breast cancer. |
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Definition
| The variability in the phenotype. Different mutations will have different degrees of a phenotype. |
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Definition
| When A/A has a more severe phenotype than A/a, but A/a still expresses the phenotype. a/a is the wild-type. |
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| Sex-limited or Sex-influenced |
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Definition
| Expression is only found in one sex or expression is different based on sex. |
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Definition
| Both alleles in a heterozygote are fully expressed -- it is neither dominant or recessive. A good example is blood type. |
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| Recessive condition. Can have pancreatic insufficiency (85%) or not. Includes recurrent respiratory disease, failure to thrive, sticky bowel movement at birth (meconium ileus) is solid, rectal prolapse. |
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Definition
| Anemia associated with hemolysis (breaking of red blood cells). Causes functional asplenia (absence of spleen), risk for serious infections, and pain crises. Prevent this by staying hydrated and getting your vaccinations. Can have HbC or HbS depending on the mutation -- C is usually less severe than S. |
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Term
| Hereditary Hemochromatosis |
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Definition
| HH is an iron overload condition. Can cause large liver, large heart (cardiomyopathy leading to cardiac failure and dysrhythmias), endocrinopathies like diabetes, increased skin pigmentation, arthritis. Also causes fatigue, weight loss, abdominal pain. This is because they have a problem with transferrin, which transports iron. Only 20-45% of the binding sites work so they absorb more iron. |
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Term
| Hardy-Weinberg Equilibrium |
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Definition
| p^2 + 2pq + q^2 = 1 P+q = 1 |
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Term
| Coefficient of Relationship |
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Definition
| R = degree of relationship between two individuals. To calculate that, find the closest shared common ancestor. REMEMBER, there may be two (ie, grandma and grandpa). Trace through the tree to the relative in question multiplying by ½ at each step. Add both together if multiple relatives. |
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Definition
| Random, called lyonization. Happens at the 64 cell stage. Called the barr body. Starts at the x-inactivation center, Xq13. The XIST gene produces an RNA product that leads to methylation. |
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Term
| What are Mendel's two laws? |
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Definition
| Segregation and independent assortment |
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