ATS2458 Lecture Notes - Lecture 3: Mendelian Inheritance, Haplotype, Autosome

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peachwolf588

20 Jan 2017

School

Monash University

Department

General Education Studies

Course

ATS2458

Professor

Asher Flynn

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Document Summary

The basic unit of heredity is the gene. Every individuals inherits two copies of each gene, one is inherited from the mother while the other is from the father. Variations, or in other words polymorphisms, within these gene pairs and pair combinations account for many of the observable differences between two individuals. As genes are strung up on the chromosome in a linear fashion we can also look at the combinations of variance in one or several genes. This is called haplotype (series of alleles on a single chromosome). It refers, therefore, to the order of alleles on a single chromosome. Haplotype analysis is a useful way of applying genotype information in disease gene discovery. The chance of a child to inherit one or the other of the two haplotypes present in each parent is 50%. The observable characteristics of an individual are called the phenotype.

Related Questions

These all relate to exceptions to the inheritance patterns encountered by Mendel.â

Why do multiple and lethal alleles often result in modifications of the classic Mendelian monohybrid and dihybrid ratios?

Select the four correct statements.

-When an essential gene is mutated, it can result in a lethal phenotype. There are no classic Mendelian monohybrid and dihybrid ratios.

-In the case of codominance, heterozygotes produce gene products from both alleles of a gene. Classic Mendelian monohybrid and dihybrid ratios are modified by codominance.

-In the case of incomplete dominance, the phenotype of the heterozygote is distinct from and often intermediate to the phenotypes of homozygous individuals. Classic Mendelian monohybrid and dihybrid ratios are modified by incomplete dominance.

-Genes exist in a large number of allelic versions and a diploid organism has two homologous gene loci that may be occupied by different alleles of the same gene. This can result in many different phenotypes for traits, which may not follow typical Mendelian ratios.

-When an essential gene is mutated, it can result in a lethal phenotype. This results in a modification of classic Mendelian ratios.

-The phenotype of the heterozygous genotype is distinct from and often intermediate to the phenotypes of the homozygous genotypes. The joint expression of both alleles in a heterozygote is called codominance. There are no classic Mendelian monohybrid and dihybrid ratios.

-Genes exist in a large number of allelic versions, but in a diploid organism, only one allele of the gene can occupy one homologous gene loci. Classic Mendelian inheritance cannot explain this phenomenon.

-Each gene produces a unique gene product. The effect of one allele in a heterozygote completely masks the effect of the other. Classic Mendelian genetics cannot explain this phenomenon.

Are the following genetic mutation positive for the 3 characteristics listed below - Phenylketonuria (PKU), Smith-Lemli-Opitz syndrome (SLOS), Alzheimerâs disease, Sickle cell anemia?

1. It is inherited (at least in some individuals or families) as a single-gene disorder (this means that a disorder where many cases are due to a mix of multiple contributing genes and environmental factors, such as heart disease or Alzheimerâs, could still be chosen if you focus on those instances with a single-gene cause)

2. It demonstrates at least one non-Mendelian characteristic (incomplete penetrance, variable expressivity, sex inflence, sex limited multiple alleles, or incomplete dominance) in its inheritance pattern

3. It is caused by mutations in a gene that has been identified and characterized.

burgundybat76

To study the function of the essential cytosolic Hsc70 genes in yeast, researchers constructed a shuttle vector in which a copy of the Hsc70 gene was ligated to the GAL1 promoter. The vector was then introduced into haploid yeast cells in which all four copies of the Hsc70 genes had been disrupted. Following introduction of the vector, you would expect that:

the yeast cells would grow on galactose but not glucose medium.

the yeast cells would grow on glucose but not galactose medium.

the yeast cells would grow on either glucose or galactose medium.

on transfer to either glucose or galactose medium, the vector-carrying cells would eventually stop growing because of insufficient Hsc70 activity.

A haplotype is a set of closely linked genetic markers on a particular chromosome that tend to be inherited together. The genetic technique that looks at inheritance patterns and uses haplotypes in determining gene locations is:

candidate gene approach

all are correct

linkage disequilibrium mapping

linkage mapping

To inactivate the function of a wild-type small GTPase one could introduce:

		an RNAi to silence the expression of the guanine nucleotide exchange factor.
		Cre recombinase.
		Cas9.
		a dominant negative allele of a GTPase gene that binds to and inactivates a guanine nucleotide exchange factor.

ATS2458 Lecture Notes - Lecture 3: Mendelian Inheritance, Haplotype, Autosome

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