CH 24 SG Flashcards
autosomes
Chromosome pairs that are the same between the sexes; in humans, but the X and Y chromosomes
What are the patterns of X-linked inheritance?
These recessive conditions are usually only present in males because they don’t have another X to neutralize it (hemophilia / Duchenne muscular dystrophy / red-green color blindness)
How does changes in the chromosome number affect an individual?
disrupt the delicate balance of gene products within cells, affecting growth, development, and function (Down (21) / Turner /Klinefelter Syndrome)
How do changes to the structure of chromosomes have detrimental effects?
(deletion, inversion, translocation, duplication) disrupt the normal processes of gene expression and protein production (Down (21)/Cri-du-chat syndrome)
Why do linked genes not follow the law of independent assortment?
they are located on the same chromosome and are inherited together more often than expected if they were on different chromosomes
sex chromosomes
Chromosomes that differ between the sexes and humans these present the X and Y chromosomes
Why are changes to the number of sex chromosomes usually more minor than changes to the number of autosomes?
Sex chromosomes only determine one’s sex it doesn’t have much effect but having an extra/missing chromosome(s) has a greater effect w/in one chromosome is large amounts of DNA (can disrupt a delicate system)
Sex-linked
Trait controlled by a gene on a sex chromosome; often described as either X-linked / Y-linked (hemophilia or color blindness)
X-linked
Allele that is located on an X chromosome; not all X-linked genes code for sexual characteristics
Color blindness
Inability to detect specific wavelengths of light associated w/ color; the inability to see red-green is the most common type of
Duchenne muscular dystrophy
Genetic disorder that is characterized by a wasting of muscle tissue; displays an X-linked recessive pattern of inheritance
Fragile X syndrome
Genetic condition caused by an abnormal number of nucleotide repeats; named after the appearance, and not physical characteristics, of the chromosome
Hemophilia
Genetic disorder that is caused by a deficiency of a clotting factor in the blood
Karyotype
Chromosomes arranged by pairs according to their size, shape, and general appearance in mitotic metaphase
Nondisjunction
Failure of the homologous chromosomes or sibling offspring to separate during either mitosis/meiosis; produces cells w/ abnormal chromosome #
Trisomy
Chromosome condition in which a diploid cell has one more chromosome than normal; designated as 2n + 1 (better tolerated)
Monosomy
Chromosome condition in which a diploid cell has one less chromosome than normal; designated as 2n - 1
Barr body
(inactive X chromosome) Dark-staining body in the cell nuclei of female mammals that contains a condensed, named after its discoverer, Murray Barr
Turner syndrome
F (45, X) a genetic condition affecting females where one of the two X chromosomes is missing or altered. (physical and health-related issues, short stature, reduced ovarian function, and potential heart problems)
Klinefelter syndrome
M (47/48,XXY/XXXY) genetic condition in males when an extra X chromosome (XXY) is affecting development, infertility, and many individuals experience delayed or incomplete puberty, reduced muscle mass, Gynecomastia, Small testes, etc.
Poly-X
F (47/48,XXX/XXXX) a female individual has three X chromosomes instead of the usual two. This can lead to a range of physical and behavioral problems) many individuals with Trisomy X experience mild symptoms or none at all
Jacobs syndrome
M (47,XYY) syndrome, is a genetic condition in males have extra Y chromosome. Delayed development, learning difficulties, and behavioral problems (many individuals with XYY syndrome have no obvious symptoms)
Chromosomal mutations
Changes in the physical structure of a chromosome; includes deletion, duplications, inversions, and translocations
Deletion
Change in chromosome structure in which the end of the chromosome breaks off or two simultaneous breaks lead to the loss of an internal segment; often causes abnormalities (Cri-du-chat syndrome)
