How do I find map distance with test cross?

Question

 

 

 

 

 

 

 

 

Any help would be appreciated!

 

 

Here's my data from test cross:

 

naked white males    X      F1 females

phenotype                    males      females
glazed naked white          193       197
glazed naked cardinal       186       186
glazed naked maroon       202       202
glazed naked                   187       198
glazed white                    192       198
glazed cardinal                195        192
glazed maroon                 191       199
glazed                             206       202
naked white                     193       195
naked cardinal                 198       196
naked maroon                 203        201
naked                             184       197
white                              194       195
cardinal                          197       193
maroon                          201       188
wild type                        197       208

Answer 1

Data Overview:

You provided counts from a test cross involving various phenotypes, with data split between males and females. The phenotypes include traits like "naked" vs. "glazed" and color variants such as "white," "cardinal," "maroon," and "wild type." The counts are fairly balanced across sexes, though some differences suggest possible sex-linked inheritance.

Data Organization:

- Counts for each phenotype are listed for males and females.

- Total counts across all phenotypes are approximately 3,229 males and 3,095 females, totaling 6,324 individuals.

Key Observations:

- Counts are similar within most phenotypes between sexes.

- Slight differences, such as higher female counts for "wild type," may indicate sex linkage or other inheritance patterns.

- Phenotypes involve multiple traits that could be linked or segregate independently.

Analysis Approach:

- To understand inheritance, a Chi-square test for independence was proposed.

- The goal is to determine whether the distribution of phenotypes differs significantly between sexes, implying linkage or other inheritance patterns.

Next Steps:

- Calculate expected counts for each phenotype under the null hypothesis of independence.

- Compute the Chi-square statistic to evaluate the significance of observed differences.

- Interpret results to determine if traits are linked or inherited independently.

In summary:

You shared detailed phenotype counts from a cross, aiming to analyze inheritance patterns. The plan involves statistical testing (Chi-square) to assess whether traits are linked to sex or inherited independently, helping to understand the genetic basis of these traits.