Tamarin: Principles of Genetics, Seventh Edition in Software

Encoder QR Code in Software Tamarin: Principles of Genetics, Seventh Edition

Tamarin: Principles of Genetics, Seventh Edition
Decode QR Code 2d Barcode In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
QR Code 2d Barcode Maker In None
Using Barcode drawer for Software Control to generate, create Quick Response Code image in Software applications.
II. Mendelism and the Chromosomal Theory
QR Scanner In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
Drawing QR Code ISO/IEC18004 In C#
Using Barcode encoder for Visual Studio .NET Control to generate, create QR Code 2d barcode image in .NET framework applications.
8. Cytogenetics
QR Generator In .NET
Using Barcode encoder for ASP.NET Control to generate, create QR Code ISO/IEC18004 image in ASP.NET applications.
Printing QR Code JIS X 0510 In VS .NET
Using Barcode drawer for VS .NET Control to generate, create Denso QR Bar Code image in Visual Studio .NET applications.
The McGraw Hill Companies, 2001
Paint QR In VB.NET
Using Barcode creator for Visual Studio .NET Control to generate, create QR Code JIS X 0510 image in Visual Studio .NET applications.
EAN / UCC - 13 Generation In None
Using Barcode printer for Software Control to generate, create GS1-128 image in Software applications.
Eight
EAN-13 Generation In None
Using Barcode generator for Software Control to generate, create UPC - 13 image in Software applications.
Generating Barcode In None
Using Barcode generator for Software Control to generate, create barcode image in Software applications.
Cytogenetics
Painting Code 128 Code Set B In None
Using Barcode maker for Software Control to generate, create Code 128 Code Set A image in Software applications.
Encoding Bar Code In None
Using Barcode encoder for Software Control to generate, create bar code image in Software applications.
Wild-type
Draw ISBN In None
Using Barcode maker for Software Control to generate, create International Standard Book Number image in Software applications.
GS1 128 Recognizer In Visual Basic .NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in Visual Studio .NET applications.
Heterozygous Bar
Paint UPC-A Supplement 5 In VB.NET
Using Barcode encoder for .NET Control to generate, create GTIN - 12 image in VS .NET applications.
Print EAN-13 Supplement 5 In None
Using Barcode drawer for Font Control to generate, create GTIN - 13 image in Font applications.
Homozygous Bar
Code 128A Creator In None
Using Barcode generator for Office Word Control to generate, create Code 128 image in Office Word applications.
Barcode Recognizer In C#
Using Barcode scanner for .NET Control to read, scan read, scan image in VS .NET applications.
Heterozygous Doublebar
Print Code-128 In Java
Using Barcode drawer for Java Control to generate, create Code128 image in Java applications.
Barcode Generation In Java
Using Barcode creator for Java Control to generate, create bar code image in Java applications.
B+/ B+
B / B+
B/ B
BB / B+
800 facets Figure 8.12
350 facets
70 facets
45 facets
Bar eye in Drosophila females.
56.7 f
57.0 B B
59.5 fu
Crossover point
Bar f+ B B
Mismatch
f Doublebar
B B B
Wild-type
Unequal crossing over in a female Bar-eyed Drosophila homozygote as a result of improper pairing. A Doublebar chromosome (and concomitant wild-type chromosome) is produced by a crossover between forked (f ) and fused (fu), two anking loci.
carrier mothers increases. Molecular techniques, discussed in chapter 13, revealed the odd nature of this syndrome. Basically, the FMR-1 gene normally has between 6 and 50 copies of a three-nucleotide repeat, CCG. Chromosomes that have the fragile-site appearance have between 230 and 2,000 copies of the repeat.The number of repeats is very unstable; when carrier women transmit the chromosome, the number of repeats usually goes up. Repeat numbers above 230 inactivate the gene and thus cause the syndrome in men, who have only one copy of the X chromosome. The function of the gene is not currently known. This unusual form of inheritance, with un-
stable repeats in a gene, seems to be the mechanism in several other diseases as well, including muscular dystrophy and Huntington disease. We will discuss other unusual modes of inheritance in chapter 17.
Cri du Chat Syndrome, 46,XX or XY,5p
The syndrome known as cri du chat (French: cry of the cat) is so called because of the catlike cry that about half the affected infants make. Microcephaly (an abnormally small head), congenital heart disease, and severe mental retardation are also common symptoms. This disorder arises from a deletion in chromosome 5 ( g. 8.16); most
Tamarin: Principles of Genetics, Seventh Edition
II. Mendelism and the Chromosomal Theory
8. Cytogenetics
The McGraw Hill Companies, 2001
Variation in Chromosomal Structure
Wild-type
Doublebar
Bar region of the X chromosome of Drosophila.
Human metaphase chromosomes with the fragile-X site indicated by an arrow. (From lan Craig, Methylation
and the Fragile X, Nature [1991] 349:742. Copyright 1991 Macmillan Magazines, Ltd.)
Karyotype of individual with cri du chat syndrome, due to a partial deletion of the short arm of chromosome 5 (5p ; arrow). (Reproduced courtesy of Dr. Thomas G. Brewster, Foundation for Blood Research, Scarborough, Maine.)
Tamarin: Principles of Genetics, Seventh Edition
II. Mendelism and the Chromosomal Theory
8. Cytogenetics
The McGraw Hill Companies, 2001
Eight
Cytogenetics
other deletions studied (4p , 13q , 18p , 18q ) also result in microcephaly and severe mental retardation. The rarity of viable deletion heterozygotes is consistent with the fact that viable monosomics (having a single chromosome of a pair) are rare. An individual heterozygous for a deletion is, in effect, monosomic for the deleted region of the chromosome. Evidently, monosomy or heterozygosity for larger deleted regions of a chromosome is generally lethal in human beings.
VA R I A T I O N I N CHROMOSOME NUMBER
Anomalies of chromosome number occur as either euploidy or aneuploidy. Euploidy involves changes in whole sets of chromosomes; aneuploidy involves changes in chromosome number by additions or deletions of less than a whole set.
Aneuploidy
An explanation for the terminology of aneuploid change appears in table 8.1. A diploid cell missing a single chromosome is monosomic. A cell missing both copies of that chromosome is nullisomic. A cell missing two nonhomologous chromosomes is a double monosomic. A similar terminology exists for extra chromosomes. For example, a diploid cell with an extra chromosome is trisomic. Aneuploidy results from nondisjunction in meiosis or by chromosomal lagging whereby one chromosome moves more slowly than the others during anaphase, is excluded from the telophase nucleus, and is thus lost. Here, nondisjunction is illustrated using the sex chromosomes in XY organisms such as human beings or fruit ies. Four examples are shown ( g. 8.17): nondisjunction in either the male or female at either the rst or second meiotic divisions. Figure 8.18 shows the types of
zygotes that can result when these nondisjunctional gametes fuse with normal gametes. All of the offspring produced are chromosomally abnormal. The names and kinds of these imbalances in human beings are detailed later in this chapter. Bridges rst showed the occurrence of nondisjunction in Drosophila in 1916 with crosses involving the white-eye locus. When a white-eyed female was crossed with a wild-type male, typically the daughters were wildtype and the sons were white-eyed. However, occasionally (one or two per thousand), a white-eyed daughter or a wild-type son appeared. This could be explained most easily by a nondisjunctional event in the white-eyed females, where XwXw and 0 eggs (without sex chromosomes) were formed. Under this hypothesis, if a Y-bearing sperm fertilized an XwXw egg, the offspring would be an XwXwY white-eyed daughter. If a normal X -bearing sperm fertilized the egg without sex chromosomes, the result would be an X 0 wild-type son. Subsequently, these exceptional individuals were found by cytological examination to have precisely the predicted chromosomes (XXY daughters and X0 sons). The other types produced by this nondisjunctional event are the XX egg fertilized by an X-bearing sperm and the 0 egg fertilized by the Y-bearing sperm. The XXX zygotes are genotypically XwXwX , or wild-type daughters (which usually die), and Y0 ies (which always die).
Copyright © OnBarcode.com . All rights reserved.