Mendelian Genetics Part 2 - Sex-Linked Traits, Pedigrees, and Probability

Flashcards based on Lecture 04 covering sex-linked traits in Drosophila, human pedigree analysis, probability rules, binomial expansion, and chi-square statistical tests.

Thomas Hunt Morgan

A scientist who received a Nobel Prize for discovering that chromosomes contain linear arrangements of genes through his genetic experiments with fruit flies.

White-Eyed Fly Mutation ($w$)

A sex-linked recessive mutation in Drosophila discovered by Thomas Hunt Morgan, providing the first definitive evidence that genes reside on chromosomes.

Hermann Joseph Muller

A drosophilist who won a Nobel Prize for his discovery that X-rays can produce genetic mutations.

CFTR

An acronym for Cystic Fibrosis Transmembrane Conductance Regulator, the gene involved in cystic fibrosis.

Human Pedigree Symbols

Standardized chart symbols where circles represent females, squares represent males, filled shapes represent affected individuals, and double lines indicate consanguineous matings.

Recessive Inheritance Pattern (Pedigree)

An inheritance pattern characterized by two unaffected heterozygous parents having on average $25\%$ affected offspring, and two affected parents producing $100\%$ affected offspring.

Dominant Inheritance Pattern (Pedigree)

An inheritance pattern where an affected individual must have inherited the gene from at least one affected parent.

Probability

The likelihood that a specific event will occur in the future, defined as $\text{Probability} = \frac{\text{Number of times an event occurs}}{\text{Total number of events}}$.

Product Rule

A probability rule stating that the chance that two or more independent events will occur together equals the product of their individual probabilities.

Binomial Expansion Equation

A statistical equation representing all possibilities for a given set of unordered events, expressed as $P = \frac{n!}{x!(n-x)!} p^x q^{n-x}$.

Factorial ($n!$)

The product of all positive integers from $n$ down to 1, where $0! = 1$ by definition.

Chi Square Test ($\chi^2$)

A statistical method used to evaluate goodness of fit between observed data ($O$) and expected data ($E$), calculated as $\text{x}^2 = \frac{\text{Sum}(O - E)^2}{E}$.

Degrees of Freedom (Chi Square)

A calculation used in chi square analysis defined as $\text{degrees of freedom} = n - 1$, where $n$ is the number of expected phenotypic categories.