X-linked

(adjective)

Associated with the X chromosome.

Related Terms

  • sex chromosomes
  • hemizygous
  • carrier

Examples of X-linked in the following topics:

  • Sex-Linked Traits

    • When a gene being examined is present on the X chromosome, but not on the Y chromosome, it is said to be X-linked.
    • Eye color in Drosophila was one of the first X-linked traits to be identified, and Thomas Hunt Morgan mapped this trait to the X chromosome in 1910.
    • Males are said to be hemizygous, because they have only one allele for any X-linked characteristic.
    • When they inherit one recessive X-linked mutant allele and one dominant X-linked wild-type allele, they are carriers of the trait and are typically unaffected.
    • Eye color in Drosophila is an example of a X-linked trait
  • Chromosomal Theory of Inheritance

    • At that time, he already knew that X and Y have to do with gender.
    • He was able to conclude that the gene for eye color was on the X chromosome.
    • This trait was thus determined to be X-linked and was the first X-linked trait to be identified.
    • Males are said to be hemizygous, in that they have only one allele for any X-linked characteristic.
    • In Drosophila, the gene for eye color is located on the X chromosome.
  • The Definite Integral

    • A definite integral is the area of the region in the xyxyxy-plane bound by the graph of fff, the $x−axis,andtheverticallines-axis, and the vertical lines −axis,andtheverticallinesx=aand and andx=b$.
    • Given a function fff of a real variable x and an interval [a,b][a, b][a,b] of the real line, the definite integral $\int_{a}^{b}f(x)dx$ is defined informally to be the area of the region in the $xy−planeboundbythegraphof-plane bound by the graph of −planeboundbythegraphoff,the, the ,thex−axis,andtheverticallines-axis, and the vertical lines −axis,andtheverticallinesx = aand and andx=b,suchthattheareaabovethe, such that the area above the ,suchthattheareaabovethex−axisaddstothetotal,andthattheareabelowthe-axis adds to the total, and that the area below the −axisaddstothetotal,andthattheareabelowthex$-axis subtracts from the total.
    • For example, consider the curve $y = f(x)$ between 0 and x = 1 with $f(x) = \sqrt{x}.$
    • As for the actual calculation of integrals, the fundamental theorem of calculus, due to Newton and Leibniz, is the fundamental link between the operations of differentiating and integrating.
    • Applied to the square root curve, $f(x) = x^{1/2}$, the theorem says to look at the antiderivative:
  • The Fundamental Theorem of Calculus

    • The fundamental theorem of calculus is a theorem that links the concept of the derivative of a function to the concept of the integral.
    • The fundamental theorem of calculus is a theorem that links the concept of the derivative of a function to the concept of the integral.
    • That is, fff and FFF are functions such that, for all $xin in in[a,b],, ,F'(x) = f(x)$.
    • By definition, the derivative of $A(x)isequalto is equal to isequalto\frac{A(x+h)−A(x)}{h}as as ash$ tends to zero.
    • By replacing the numerator, $A(x+h)−A(x),by, by ,byhf(x)anddividingby and dividing by anddividingbyh,, ,f(x)$ is obtained.
  • Areas to the Left and Right of x

    • This area is represented by the probability P ( X < x ) .
    • The area to the right is then P ( X > x ) = 1 − P ( X < x ) .
    • Remember, P ( X < x ) = Area to the left of the vertical line through x.
    • P ( X > x ) = 1 − P ( X < x ) = .
    • P ( X < x ) is the same as P ( X ≤ x ) and P ( X > x ) is the same as P ( X ≥ x ) for continuous distributions.
  • The Natural Logarithmic Function: Differentiation and Integration

    • for $\left | x \right | \leq 1$ (unless $x = -1$).
    • Substituting $x − 1for for forx,weobtainanalternativeformfor, we obtain an alternative form for ,weobtainanalternativeformfor\ln(x)$ itself:
    • $\ln(x) = (x - 1) - \dfrac{(x - 1)^{2}}{2} + \dfrac{(x - 1)^{3}}{3} - \cdots$ 
    • for $\left | x -1 \right | \leq 1$ (unless $x = 0$).
    • Here is an example in the case of $g(x) = \tan(x)$:
  • Trigonometric Limits

    • For $0 < x < \frac{ \pi}{2},, ,\sin x < x < \tan x.$
    • $\displaystyle{\lim_{x \to 0} \left ( \frac{x}{\sin x} \right ) = 1}$
    • $\displaystyle{\lim_{x \to 0} \left ( \frac{\sin x}{x} \right ) = 1}$
    • $\displaystyle{\frac{(1−\cos x)(1+\cos x)}{x(1+\cos x)}=\frac{(1−\cos^2x)}{x(1+\cos x)}=\frac{\sin^2x}{x(1+\cos x)}= \frac{\sin x}{x} \cdot \frac{\sin x}{1+\cos x}}$
    • $\displaystyle{\lim_{x \to 0}\left ( \frac{\sin x}{x} \frac{\sin x}{1 + \cos x} \right ) = \left (\lim_{x \to 0} \frac{\sin x}{x} \right ) \left ( \lim_{x \to 0} \frac{\sin x}{1 + \cos x} \right ) = \left (1 \right )\left (\frac{0}{2} \right )= 0}$
  • Making Inferences About the Slope

    • This is sometimes called the unique effect of $x$ on $y$.
    • In contrast, the marginal effect of $xon on onycanbeassessedusingacorrelationcoefficientorsimplelinearregressionmodelrelating can be assessed using a correlation coefficient or simple linear regression model relating canbeassessedusingacorrelationcoefficientorsimplelinearregressionmodelrelatingxto to toy;thiseffectisthetotalderivativeof; this effect is the total derivative of ;thiseffectisthetotalderivativeofywithrespectto with respect to withrespecttox$.
    • This may imply that some other covariate captures all the information in $x,sothatoncethatvariableisinthemodel,thereisnocontributionof, so that once that variable is in the model, there is no contribution of ,sothatoncethatvariableisinthemodel,thereisnocontributionofxtothevariationin to the variation in tothevariationiny$.
    • In this case, including the other variables in the model reduces the part of the variability of yyy that is unrelated to $x,therebystrengtheningtheapparentrelationshipwith, thereby strengthening the apparent relationship with ,therebystrengtheningtheapparentrelationshipwithx$.
    • In some cases, it can literally be interpreted as the causal effect of an intervention that is linked to the value of a predictor variable.
  • Summary of Formulas

    • ( x − $\bar{x}$ ) or ( x − µ ) = Deviations from the mean (how far a value is from the mean)
    • ( x − $\bar{x}$)2 or ( x − µ )2 = Deviations squared
    • $\bar{x} = \frac{\sum{x}}{n} or x = \frac{\sum{f} \cdot x}{n}\bar{x} = \frac{\sum{x}}{n} or x = \frac{\sum{f} \cdot x}{n}$
    • $s = \sqrt{\frac{\sum(x \bar{x})^2}{n 1}}or s = \sqrt{\frac{\sum{f} \cdot ( x \bar{x})^2}{n-1}}$
    • $s = \sqrt{\frac{\sum(x \bar{x})^2}{N}}or s = \sqrt{\frac{\sum{f} \cdot ( x \bar{x})^2}{N}}$
  • Integration By Parts

    • $\displaystyle{\int u(x) v'(x) \, dx = u(x) v(x) - \int u'(x) v(x) \ dx}$
    • $dv = \cos(x)\,dx \\ \therefore v = \int\cos(x)\,dx = \sin x$
    • $\begin{aligned} \int x\cos (x) \,dx & = \int u \, dv \\ & = uv - \int v \, du \\ & = x\sin (x) - \int \sin (x) \,dx \\ & = x\sin (x) + \cos (x) + C \end{aligned}$
    • Similarly, the area of the red region is $A_2=\int_{x_1}^{x_2}y(x)dx$.
    • The total area, A1+A2A_1+A_2A​1​​+A​2​​, is equal to the area of the bigger rectangle, $x_2y_2,minustheareaofthesmallerone,, minus the area of the smaller one, ,minustheareaofthesmallerone,x_1y_1:: :\int_{y_1}^{y_2}x(y)dy+\int_{x_1}^{x_2}y(x)dx=\biggl.x_iy_i\biggl|_{i=1}^{i=2}$.
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