A Geneticist Is Investigating the Inheritance of Two Autosomal Recessive

question 21

Short Answer

A geneticist is investigating the inheritance of two autosomal recessive genes in mice, one for obesity (LEP) and another for autism (oprm1). The table below provides the number of offspring observed, for each phenotype, when dihybrid mice are testcrossed: $$\begin{array} { | l | c | l | l | l | l | } \hline \text { Phenotype } & \text { Observed(O) } & \text { Expected } ( \mathrm { E } ) & \mathrm { O } - \mathrm { E } & ( \mathrm { O } - \mathrm { E } ) 2 & ( \mathrm { O } - \mathrm { E } ) 2 / \mathrm { E } \\\hline \text { wild- type } & 88 & & & & \\\hline \text { obese } & 68 & & & & \\\hline \text { autistic } & 64 & & & & \\\hline \text { obese, autistic } & 80 & & & & \\\hline & & & & & \sum ( \mathrm { O } - \mathrm { E } ) ^ { 2 } / \mathrm { E } = \\\hline\end{array}$$ Fill in the table above and determine:
a. the chi- square (χ²) value (to the nearest hundredth) for the chance hypothesis that the two genes assort independently
b. the degrees of freedom
c. whether or not you would reject your chance hypothesis that the two genes assort independently, based on approximate P value, and the justification for why

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Definitions:

Classical Economists

Economists of the late 18th and 19th centuries who believed in free markets, minimal government intervention, and the importance of competition.

Aggregate Demand

This term refers to the total amount of goods and services demanded in the economy at a given overall price level and in a given time period.

Laissez Faire

An economic policy or attitude of letting markets operate without government interference or regulation.

Recessions

Periods of temporary economic decline during which trade and industrial activity are reduced, typically recognized by a fall in GDP in two successive quarters.