Skip to main content
Ch. 5 - Genetic Linkage and Mapping in Eukaryotes
Sanders - Genetic Analysis: An Integrated Approach 3rd Edition
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoSanders 3rd EditionCh. 5 - Genetic Linkage and Mapping in EukaryotesProblema 21a
Capitolo 5, Problema 21a

Gene R and gene T are genetically linked. Answer the following questions concerning a dihybrid organism with the genotype Rt/rT:


If r = 0.20, give the expected frequencies of gametes produced by the dihybrid.

Guida verificata passo dopo passo
1
Understand that genetic linkage means that genes R and T are located close to each other on the same chromosome, and their alleles are less likely to assort independently during meiosis.
Identify the parental and recombinant gametes. For the genotype Rt/rT, the parental gametes are Rt and rT, while the recombinant gametes are RT and rt.
Recall that the recombination frequency (r) represents the proportion of recombinant gametes produced. Here, r = 0.20, meaning 20% of the gametes are recombinant.
Divide the recombination frequency equally between the two recombinant gametes (RT and rt). Each recombinant gamete will have a frequency of r/2 = 0.20/2 = 0.10.
Calculate the frequencies of the parental gametes (Rt and rT). Since the total frequency of all gametes must equal 1, the parental gametes will have a combined frequency of 1 - r = 1 - 0.20 = 0.80. Divide this equally between the two parental gametes, so each parental gamete will have a frequency of 0.80/2 = 0.40.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
3m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Genetic Linkage

Genetic linkage refers to the tendency of genes that are located close to each other on a chromosome to be inherited together during meiosis. This phenomenon affects the assortment of alleles and can lead to non-Mendelian inheritance patterns. Understanding linkage is crucial for predicting gamete frequencies, as linked genes do not assort independently.
Video consigliato:
Percorso guidato
07:33
Chi Square and Linkage

Dihybrid Cross

A dihybrid cross involves two traits, each represented by two alleles, allowing the study of inheritance patterns for two genes simultaneously. In this case, the organism has the genotype Rt/rT, indicating heterozygosity for both genes. The expected gametes can be determined by considering the combinations of alleles that can be produced from this genotype.
Video consigliato:
Percorso guidato
15:24
Punnet Square

Gamete Frequency Calculation

Gamete frequency calculation involves determining the proportion of different gametes produced by an organism based on its genotype and the recombination frequency. In this scenario, with a recombination frequency (r) of 0.20, the expected frequencies of the parental and recombinant gametes can be calculated using the formula that incorporates the linkage and recombination rates.
Video consigliato:
Percorso guidato
21:21
Gamete Development
Pratica correlata
Domanda del libro di testo

Gene R and gene T are genetically linked. Answer the following questions concerning a dihybrid organism with the genotype Rt/rT:


Can you make a general statement about how the occurrence of two crossover events between a given pair of linked genes affects the estimate of recombination frequency?

407
views
Domanda del libro di testo

T. H. Morgan's data on eye color and wing form genetic linkage between the two genes. Test the genetic linkage (shown in the figure below) data with chi-square analysis, and show that the results are significantly different from the expectation under the assumption of independent assortment.

806
views
Domanda del libro di testo

Genetic linkage mapping for a large number of families identifies 4% recombination between the genes for Rh blood type and elliptocytosis (see Problem 18). At the Rh locus, alleles R and r control Rh+ and Rh- blood types. Allele E producing elliptocytosis is dominant to the wild-type recessive allele e. Tom and Terri each have elliptocytosis, and each is . Tom's mother has elliptocytosis and is Rh- while his father is healthy and has Rh+. Terri's father is Rh+ and has elliptocytosis; Terri's mother is Rh- and is healthy.


What is the probability that the first child of Tom and Terri will be Rh− and have elliptocytosis?

750
views
Domanda del libro di testo

A group of families in which an autosomal dominant condition is present are studied to determine lod scores for possible genetic linkage between three RFLP markers (R1, R2, and R3) and the disease gene. The chart shows lod scores at each of the recombination distances (θ values) tested. Provide an interpretation of the lod score results for each RFLP. Be specific about any significant evidence of genetic linkage.

441
views
Domanda del libro di testo

Genetic linkage mapping for a large number of families identifies 4% recombination between the genes for Rh blood type and elliptocytosis (see Problem 18). At the Rh locus, alleles R and r control Rh+ and Rh- blood types. Allele E producing elliptocytosis is dominant to the wild-type recessive allele e. Tom and Terri each have elliptocytosis, and each is . Tom's mother has elliptocytosis and is Rh- while his father is healthy and has Rh+. Terri's father is Rh+ and has elliptocytosis; Terri's mother is Rh- and is healthy.


What is the probability that a child of Tom and Terri who is Rh+ will have elliptocytosis?

750
views
Domanda del libro di testo

Gene R and gene T are genetically linked. Answer the following questions concerning a dihybrid organism with the genotype Rt/rT:


If two crossover events occur between these two genes, what are the genotypes of the recombinant chromosomes?

450
views