MMSC491 Exam 2 Questions and Answers (With 100% Error-Free Answers) Latest 2024 SOLVED.

MMSC491 Exam 2 Questions and Answers (With 100% Error-Free Answers) Latest 2024 SOLVED. phenotype correct answers the set of observable characteristics of an individual resulting from the interaction of its genotype genotype correct answers the genetic constitution of an individual organism homozygous correct answers having two identical alleles of a particular gene or genes heterozygous correct answers having two different alleles of a particular gene or genes compound heterozygote correct answers The presence of two different mutated alleles at a particular gene locus example of compound heterozygote correct answers Tay-Sachs disease, GM2-gangliosidosis, AB variant, and Sandhoff disease might easily have been defined together as a single disease, because the three disorders are associated with failure of the same enzyme and have the same outcome dominant correct answers dominance 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 example of dominance correct answers V-shaped hairline, Almond-shaped eyes, Right handedness, Detached earlobes, Dark hair Brown eyes, baldness recessive correct answers Refers 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 correct answers Cleft chin, dimples, freckles, Straight hairline, Round eyes, Left handedness, Attached earlobes, Blond hair, red hair, Blue eye co-dominant correct answers refers 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 correct answers blood 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 correct answers a diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors from one generation to the next sib correct answers sibling male correct answers square MMSC491 Exam 2 Questions and Answers (With 100% Error-Free Answers) Latest 2024 Rated A+! female correct answers circle sex unstated correct answers diamond autosomal dominant correct answers Autosomal 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 correct answers Huntington's disease autosomal recessive correct answers You inherit two changed genes (mutations), one from each parent. example of autosomal recessive correct answers cystic fibrosis, sickle cell anemia, and TaySachs disease consanguineous correct answers relating to or denoting people descended from the same ancestor, A feature of many recessive disorders carrier correct answers is 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 x-linked recessive correct answers most 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 correct answers more 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 correct answers if 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 autosomal dominant pedigree correct answers autosomal recessive pedigree correct answers x-linked recessive pedigree correct answers x-linked dominant pedigree correct answers x-chromosome inactivation correct answers One of the two X chromosomes is randomly and permanently inactivated in cells other than egg cells. This phenomenon is called X-inactivation or lyonization. X-inactivation ensures that females, like males, have one functional copy of the X chromosome in each body cell. barr body correct answers an inactive X chromosome in a cell with more than one X chromosome, rendered inactive in a process called lyonization, only found in females somatic mosaicism correct answers refers to the occurrence of two genetically distinct populations of cells within an individual, derived from a postzygotic mutation, a postzygotic mutation that occurs in the soma, and it may occur at any developmental stage or in adult tissues germ-line mosaicism correct answers a mutation that is limited to the gonads and can be transmitted to offspring, some sperm or eggs have a gene mutation that may not be present in other tissues of the body (such as the blood, which is typically used for genetic testing). locus heterogeneity correct answers explains how parents who are both affected with the same common recessive disorder produce multiple unaffected children examples of locus heterogeneity correct answers Recessively inherited deafness is the classic example (sensorineural hearing impairment mostly shows autosomal recessive inheritance, and deaf persons often choose to have children with another deaf person). If two deaf parents are homozygous for mutations at the same gene locus, one would expect that all their children would also have impaired hearing. If, instead, the parents are homozygous for mutations at two different recessive deafness loci, all their children would be expected to be double heterozygotes and have normal hearing, Usher syndrome, for example, involves profound sensorineural hearing loss, vestibular dysfunction, and retinitis pigmentosa; autosomal recessive forms can be caused by mutations at any one of at least 11 different gene loci., Bardet-Biedl syndrome (PMID ) provides another illustrative example. Allelic and phenotypic heterogeneity correct answers Many different mutations in one gene can have the same effect and produce similar phenotypes examples of allelic and phenotypic heterogeneity correct answers For example, β-thalassemia results from a deficiency of β-globin and can arise by any number of different mutations in the hemoglobin β chain (HBB) gene. Different mutations in a single gene can also often result in different phenotypes. That can arise in two ways: either different types of mutation somehow have different effects on how the underlying gene works—which we consider here—or some factors outside the disease locus have varying effects on the phenotype (described below)., Ex. Duchenne and Becker muscular dystrophies (OMIM 310200 and 300376, respectively) represent severe and mild forms of the same type of muscular dystrophy and are both examples of dystrophinopathies penetrance correct answers the probability that a person who has a mutant allele will express the disease phenotype non-penetrance correct answers the disorder can sometimes appear to skip a generation so that a person who must have inherited the disease allele is unaffected age-related penetrance correct answers In some disorders, there is a late age at onset so that the penetrance is initially very low but then increases with age. Age-related penetrance means a late onset of symptoms, and quite often the disease first manifests in adults. example of age-related penetrance correct answers Huntington disease (PMID ) is a classic example of a late-onset single-gene disorder. Age-at-onset curve: In Huntington disease an unaffected person who has an affected parent will have a 50% a priori risk that decreases with age (see Figure 5.13); if one is still free of symptoms by age 60, for example, the chance of developing the disease falls to less than 20%. imprinting correct answers The parent-of-origin effects are due to an epigenetic mechanism known as imprinting. The mutant allele that is not expressed is often described as the imprinted allele. example of imprinting correct answers Beckwith-Wiedemann syndrome is said to be paternally imprinted, because paternally inherited alleles are not expressed. anticipation correct answers expressed at an earlier age and become increasingly severe with each generation example of anticipation correct answers fragile X mental retardation syndrome, myotonic dystrophy, and Huntington disease are caused by unstable mutations (often called dynamic mutations) whose characteristics can change after they undergo DNA replication cis-acting elements correct answers regions of non-coding DNA which regulate the transcription of neighboring genes, limited to a single DNA molecule on which is resides Ex. operator in the lac operon trans-acting factor correct answers regulate gene transcription by binding directly or through an intermediate protein to the gene at a particular DNA sequence, called a cis-regulatory region, free to migrate by diffusion so as to recognize and bind specific short target nucleic acid sequences, Ex. RNA polymerase, repressor, TATA Binding Protein, TFIIB, CAP, tryptophan epigenetic event correct answers heritable changes in gene expression that are, unlike mutations, not attributable to alterations in DNA sequence. Two predominant epigenetic mechanisms are DNA methylation and histone modification promoter correct answers a region of DNA upstream of a gene where relevant proteins (such as RNA polymerase and transcription factors) bind to initiate transcription of that gene enhancers correct answers cis-acting DNA sequences that can increase the transcription of genes EMAIL ME: EMAIL ME: silencer correct answers regulatory DNA elements that reduce transcription from their target promoters; they are the repressive counterparts of enhancers insulator correct answers a type of cis-regulatory element known as a long-range regulatory element, can block inappropriate interactions between enhancers and promoters notably the CTCF regulator DNA looping correct answers occurs when a protein or a complex of proteins simultaneously binds to two different sites on DNA with looping out of the intervening DNA, allows directy physical interactions between proteins bound to a distant cis-actin element that regulates a fene with some o fhte many proteins bound to the gene's promoter zinc finger motif correct answers involves the binding of Zn2+ ion by four conserves amino acids so as to form a loop leucine zipper correct answers a helical stretch of amino acids rich in hydrophobic leucine residues, aligned on one side of the helix, Facilitates the dimerization of the protein by interdigitation of two leucine-containing helices on different molecules combinatorial effects correct answers Different transcription factors work in concert by binding to adjacent recognition sequences