Term
| What two factors do single-gene disorder patterns depend on? |
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Definition
1) whether the phenotype is dominant or recessive
2) whether the gene locus is on the autosome or sex chromosome |
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Term
| Define autosomal dominant. |
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Definition
| Phenotypic expression when only one chromosome of a pair carries the mutant allele and the other has a WT allele at that locus. It can occur on chromosomes 1 to 22 hence, affecting males and females equally. |
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Term
| Define autosomal recessive. |
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Definition
| Phenotypic expression when both chromosomes of a pair carry mutant alleles at a locus. It can occur on chromosomes 1 to 22 hence, affecting males and females equally. |
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Term
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Definition
| When mutant allele is on a sex chromosome (X or Y). |
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Term
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Definition
| Set of alleles that make up a person’s genetic constitution. |
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Term
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Definition
| Observable expression of a genotype as a morphological, clinical, cellular, or biochemical trait. |
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Term
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Definition
| Pair of identical alleles at a locus encoded in nuclear DNA. |
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Term
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Definition
| Pair of alleles at a locus is different. |
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Term
| Define compound heterozygote. |
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Definition
| Genotype in which two different mutant alleles of the same gene are present. |
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Term
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Definition
| Case where a male has an abnormal allele for a gene located on the X Chromosome and there is no other copy of the gene; is neither homo- or heterozygous. |
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Term
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Definition
| Phenotypic expression of two different alleles for a locus occurs. |
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Term
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Definition
| Classification of a disease when dominant disorders are more severe in homozygotes than in heterozogytes. |
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Term
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Definition
| Graphical representation of the family tree. |
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Term
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Definition
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Term
| Define consultant and what is its symbol? |
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Definition
| Person who brings the family to attention by consulting a geneticist. Shown by an arrow. |
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Term
| Define proband and what is its symbol? |
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Definition
| aka propositus or index case is the member through whom a family with a genetic disorder is first brought to the attention of the geneticist. Completely colored shape. |
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Term
| Define consanguineous and what is its symbol? |
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Definition
| Couples who have one or more ancestors in common. Shown with a double line in a marriage. |
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Term
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Definition
| Only one affected member in a family. |
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Term
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Definition
| If disorder is determined to be due to a new mutation in the propositus. |
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Term
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Definition
| Number of offspring affected individuals with the condition can have who survive to reproductive age. |
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Term
| What is the difference between inheritance of the nuclear genome versus mitochondrial genome? |
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Definition
| Nuclear inheritance affects males and females equally; mitochondrial is matrilinear because sperm mitochondria are eliminated from the embryo so that mtDNA is inherited from the mother. |
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Term
| Who will inherit a mutation from mitochondrial inheritance? |
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Definition
| All the children of a female who is homoplasmic for a mtDNA mutation will inherit the mutation, whereas none of the offspring of a male carrying the same mutation will inherit the defective DNA. |
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Term
| Describe the concept of threshold for phenotypic expression with mtDNA. |
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Definition
| There is a spectrum of disease and it depends on whether the fraction of mutant mitochondria from the mother is greater than the threshold for phenotypic expression. |
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Term
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Definition
| When a daughter cell receives mt that contains only a pure population of normal mtDNA or of mutant mtDNA. |
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Term
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Definition
| Daughter cell receives mixture of mitochondria, some with and without mutant. |
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Term
| Define concept of mitochondrial genetic bottleneck. |
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Definition
| When the number of mtDNA molecules within developing oocytes is reduced before being subsequently amplified to the huge total seen in mature oocytes. |
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Term
| Define replicative segregation. |
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Definition
| Process during cell division whereby the mitochondria and mtDNA are randomly partitioned along with the cytoplasm. |
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Term
| How many genes are mtDNA and how many polypeptides does it encode for? |
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Definition
| 37 genes for 13 proteins; circular chromosome |
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Term
| What are the three unusual features of mt? |
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Definition
1) replicative segregation
2) homoplasmy and heteroplasmy
3) maternal inheritance |
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