BIO207H5 Chapter Notes - Chapter 14: Centimorgan, Genetic Distance, Wild Type

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emeralddog909

28 Apr 2012

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Document Summary

Gene marjers are alleles of genes, whereas dna markers are molecular markers (that is dna. Genes that are on the same chromosome are said to be syntenic. Genes that do not appear to assort independently because they are located on the same chromosome exhibit linkage and are called linked genes. Genetic analysis is the dissection of the structure and function of the genetic material. Progeny showing the parental combinations of alleles are called parentals, and progeny showing nonparental combinations of alleles are called recombinants. The process by which the recombinants are produced is called genetic recombination. Genetic maps are constructed using both gene markers and dna markers. A marker, or genetic marker, is another name for a mutation or variant that gives a distinguishable phenotype. In other words, it is an allele that marks a chromosome or a gene. regions in the genome that are polymorphic (differ among individuals) and thus can be detected by the molecular analysis of dna.

Related Questions

Q.) A geneticist is mapping the location of three markers relative to a disease causing genetic variant. Her results are shown below. Based on the results of the mapping, answer the following questions.

Marker	Recombination fraction relative to disease gene
X	0.3
Y	0.5
Z	0.1

a.) Which marker is closest to the disease-causing genetic variant? Support your answer. (2)

b.) Which marker is not linked to the disease-causing variant? Support your answer. (2)

c.) If the geneticist scored 200 chromosomes for recombination, how many recombinants did she observe for each marker? (2)

indigocricket198

For genetics:

how do we parental classes in meiosis come about ? Is there no recombination or crossing over occurring? But in my textbook it says that if recombination did not occur, nondisjunction during meiosis I would be a common, rather than a rare occurrence, and species could not retain the same number of chromosomes in successive generations.

I am confused on how linked genes have more parental types than recombination types, i understand that the linked genes are inherited together because they are close together on the same chromosome.

I guess my question is, do all chromosomes undergo recombination and crossing over in meiosis? And the parental classes are parental because were just looking for those certain linked genes that are inherited together?

thank you!

aquamarineduck901

The syntenic genes A and Z are linked. A cross between two parents, AAzz and aaZZ, produces F₁ progeny with the AaZz genotype. What are the possible arrangements of alleles on the F₁ progeny's chromosomes?

A/Z or a/z

The answer is not AZ/az

Genes that are on the same chromosome can assort independently when

they are very close together on a chromosome and crossing over occurs rarely between the genes.

they are far apart on a chromosome and crossing over occurs rarely between the genes.

they are far apart on a chromosome and crossing over occurs frequently between the genes.

they are syntenic.

Genes on the same chromosome cannot assort independently.