Term
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Definition
| genes remain intact and distinct: i.e., Genes are segregated equally into the haploid products of meiosis |
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Term
| Principle of independent assortment |
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Definition
| genes at different loci are transmitted independently |
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Term
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Definition
| refers to the different forms of DNA sequences that a gene has in a population. |
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Term
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Definition
| individual’s allelic constitution at a locus |
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Term
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Definition
| observed characteristics of an individual produced by the interaction of genes and the environment. The same genotype may produce different phenotypes in different environments. (e.g.phenylketonuria). |
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Term
| What is the first step in constructing a pedigree? |
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Definition
| figuring out the family history |
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Term
| Single Gene Inheritance (Monogenic) Nuclear Genome |
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Definition
THis is a very rare single gene defect that has a familial pattern of inheritance and transmitted on autosomal, X, or Y
The disease is likely to be severe, with the severity dependant on the location of the gene defect. It can be complicated by environmental modifiers. |
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Term
| Examples of Autosomal Dominant diseases |
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Definition
Huntington’s
Myotonic Dystrophy
Marfan syndrome(associated with the fibrillin gene) |
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Term
| Autosomal Dominant Inheritance traits |
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Definition
exhibits longitudinal transmission
see father to son transmission
heterozygotes exhibit the disorder
males and females are transmitted the disease at an equal frequency |
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Term
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Definition
this is an example of a gain of function autosomal dominant mutation of the epithelial sodium channels which leads to greater reabsorption of sodium
causes early onset hypertension |
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Term
| Loss of function mutatuion |
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Definition
| the protein is dysfunctional |
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Term
| Autosomal recessive diseases |
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Definition
Sickle cell anemia (beta globin protein)
Cystic fibrosis (CFTR)
Phenylketonuria (phenylalanine hydroxylase). |
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Term
| traits of autosomal recessive inheritance |
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Definition
2 copies of the mutant gene are needed to have the disorder
heterozygotes are carriers
males and females are affected equally
the trait skips generation
father to son transmission |
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Term
| Traits of X linked disorders |
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Definition
expressed more in men
x linked recessive and dominant are not linked to females
absence of father to son transmission |
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Term
| Examples of X linked disorders |
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Definition
Hemolytic anemia (glucose 6-phosphate dehydrogenase).
Muscular dystrophy (dystrophin).
Hemophilia A (factor VIII).
Ornithine Carbamoyltransferase deficiency.
Lesch-Nyhan syndrome (hypoxanthine-guanine phospho-ribosyl transferase) |
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Term
| examples of x dominant diseases |
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Definition
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Term
| X chromosome Inactivation |
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Definition
| during the early stages of embryo development in women one of the x chromosomes are inactivated producing a barr body. this is done to compensate for gene dosage and once done the inactivation is permanent. |
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Term
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Definition
| XIST RNA is transcribed on the inactivated x chromosome. converts the genetic material to heterochromatin |
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Term
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Definition
XO-- monosomy X chromosome
No X chromosome inactivation
Intellegence usually normal, but impaired social competence and adjustment |
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Term
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Definition
Individual does not exhibit the disease phenotype but carries the disease genotype. He or she can transmit the disease gene to the next generation.
can be seen in autosomal dominant inheritance |
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Term
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Definition
probability that a gene will have phenotypic expression.
Lack of penetrance due to modifier genes (epistasis) or environmental effects. |
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Term
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Definition
A child will be born with a disease for which there is no previous history of the disease in the family
Can occur during pregnancy |
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Term
| Factors That Complicate Mendelian Patterns |
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Definition
penetrance
new mutation
variable expression
germline mosaicism
locus and allelic heterogeneity |
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Term
| Congenital rubella syndrome |
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Definition
| a type of new mutation that is caused by an exposure to a viral infection |
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Term
| What is variable expression? |
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Definition
| Severity of the disease can vary greatly - modified by environment, modifier genes (protein variants) |
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Term
| Mutations that can lead to variable expression |
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Definition
1. Heteroplasmic mitochondrial mutation.
2. Mosaicism.
3. polymorphisms in promoter or regulatory sequences. |
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Term
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Definition
occurs when there is a mutation in only the germ cells of a person.
can be passed along to offspring
if the the person's blood is tested the genetic mutation may not be detected. |
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Term
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Definition
| Same disease, but mutations at different chromosomal loci. |
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Term
| Disease associated with locus hetergeneity |
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Definition
| Hereditary nonpolyposis colorectal cancer (autosomal dominant) is caused by defective DNA mismatch repair genes, each located on different chromosomes. |
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Term
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Definition
| Different mutatuions within the same gene |
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Term
| examples of different disorders associated with allellic heterogeneity |
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Definition
| DMD, BMD, beta hemogloblin |
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Term
| What is a compound heterozygote? |
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Definition
| 2 different mutations in 2 different locations all on the same gene |
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Term
| Examples of Beta hemoglobin allelic heterogeneity |
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Definition
| normal (glu-GAG); sickle cell (val-GTG) or hemoglobin C (lys-AAG) |
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Term
| Example of compound heterozygote |
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Definition
| - Hb E: glutamic for lysine at codon 26. not on codon 6 |
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