MMSC491 Exam 2 Questions With Verified Solutions

MMSC491 Exam 2 Questions With Verified Solutions Phenotype - answerthe set of observable characteristics of an individual resulting from the interaction of its genotype genotype - answercombination of alleles that a patient possesses (homozygous, heterozygous, & hemizygous) homozygous - answerhaving two identical alleles of a particular gene or genes heterozygous - answerhaving two different alleles of a particular gene or genes hemizygous - answerhaving only a single copy of a gene instead of the customary two copies pedigree symbols - answer dominant - answerdominance is the phenomenon of one variant of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome examples of dominance - answeralmond eye shape, right handedness, detached earlobes, dark hair, brown eyes, baldness, etc. recessive - answerrefers to a trait that is expressed only when genotype is homozygous; a trait that tends to be masked by other inherited traits, yet persists in a population among heterozygous genotypes examples of recessive - answerdimples, freckles, straight hairline, round eye shape, left handedness, attached earlobes, blond hair, red hair, blue eyes, etc. co-dominant - answerrefers to a type of inheritance in which two versions (alleles) of the same gene are expressed separately to yield different traits in an individual example of co-dominance - answerblood type. People with the AB blood type have one A allele and one B allele. Because both alleles are expressed at the same time, their blood type is AB. pedigree - answera diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors from one generation to the next medelian inheritance - answerfive basic patterns (autosomal dominant, autosomal recessive, x-linked recessive, x-linked dominant, & y-linked) autosomal dominant - answerautosomal dominant inheritance is a way a genetic trait or condition can be passed down from parent to child. One copy of a mutated (changed) gene from one parent can cause the genetic condition. A child who has a parent with the mutated gene has a 50% chance of inheriting that mutated gene. example of autosomal dominant - answerhuntington's disease autosomal recessive (carriers & compound heterozygote) - answerYou inherit two changed genes (mutations), one from each parent. example of autosomal recessive - answercystic fibrosis, sickle cell anemia, & Tay-Sachs disease consanguineous (coefficient of relationship & inbreeding) - answerrelating to or denoting people descended from the same ancestor, A feature of many recessive disorders carriers - answeris a person or other organism that has inherited a recessive allele for a genetic trait or mutation but usually does not display that trait or show symptoms of the disease, can pass on allele to offspring compound heterozygote - answeran individual who carries two different alleles at a locus resulting in a recessive phenotype example of compound heterozygote - answerTay-Sachs disease, GM2-gangliosidosis, AB variant, & Sandhoff disease x-linked recessive - answermost often occurs in males, no male-to-male transmission, Female carriers with a single mutant allele can occasionally be quite severely affected and are known as manifesting heterozygotes x-linked dominant - answermore often occurs in females, All children born to an affected mother have a 50% chance of being affected, An affected father with a single X chromosome will consistently have unaffected sons (but daughters will always be at risk because they will always inherit his affected X y-linked - answerif the altered gene that causes the disorder is located on the Y chromosome, one of the two sex chromosomes in each of a male's cells. Because only males have a Y chromosome, in Y-linked inheritance, a variant can only be passed from father to son, Rare because of the lack of genes on Y chromosome a