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39 Cards in this Set
- Front
- Back
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an individual who is heterozygous at a given genetic locus for a recessively inherited disorder
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carrier
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a gene located on either sex chromosome; most are on x chromosome
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sex linked gene
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a human genetic disease resulting in the absence of one or more blood clotting proteins
-what kind of disease? |
hemophilia
-sex-linked recessive |
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one or more chromosomes are present in extra copies or are deficient in number
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aneuploidy
-example = polyploidy |
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lies along the nuclear envelope in cells of female mammals
-represents what? |
Barr body
-inactivated x chromosome -men don't have these |
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diploid cell that has three copies of a particular chromosome instead of the normal two
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trisomy
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an organism possesses more than two complete chromosome sets
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polyploidy
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trisomy vs triploidy
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trisomy = one extra copy of a chromosome
triploidy = three complete sets of chromosomes |
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a human genetic disease characterized by developmental delays and heart and other defects that are generally treatable and not life threatening
-caused by? |
down syndrome
-trisomy of chromosome 21 |
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each gene has its own position in sequence on a chromosome
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okay okay
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XX
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female
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XY
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male
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the x chromosome has some genes that the y chromosome doesnt
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key concept!
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a male will always inherit his y chromosome from?
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HIS FATHER
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percentage of having a girl versus a boy
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50 50
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describe the x-0 system
-examples? |
males have no y chromosome, instead they simply have nothing
so females = XX males = X some insects including roaches and grasshoppers - |
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describe the z-w system
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opposite of XY
females = ZW males = ZZ -egg determines sex -true in birds, some fishes and insects |
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describe the haploid diploid system
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-ONLY SEX DETERMINATION SYSTEM THAT DOESNT INVOLVE SEX CHROMOSOMES
-in bees and ants -diploid = females -haploid = males |
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when does an embryo determine sex
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8 weeks old
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what does SRY stand for?
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sex-determining region of Y
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what does gene SRY code for?
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the development of testes, codes for a protein that regulates many other genes
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x chromosome linkage can skip the son because he receives his x chromosome from his mother, and will pass it on to his daughter
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kk
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examples of recessive x-linked diseases
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color blindness, hemophilia, duchenne muscular dystrophy
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x-linked recessive gene characterized by progressive weakening and a loss of muscle tissue
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duchenne muscular dystrophy
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x-linked
-if father is infected, he must have recessive x -if son is infected, mother must have been at least a carrier |
okay okay
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most common childhood muscular disease
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duchenne muscular dystrophy
-incurable |
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y-linked inheritance is common where?
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among populations of India
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y-linked chromosomes - only males can get them from fathers
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makes sense
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a mutational loss of one or more nucleotide pairs from a gene
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deletion
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an aberation in chromosome structure due to fusion with a fragment from a homologous chromosome, such that a portion of a chromosome is duplicated
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duplication
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an aberation in chromosome structure resulting from reattachment of a chromosomal fragment in a reverse orientation to the chromosome from which it originated
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inversion
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an aberration in chromosome structure resulting from an attachment of a chromosomal fragment to a non homologous chromosome
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reciprocal translocation
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result of nondysjunction
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aneuploidy
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males with an extra x chromosome
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klinefelter syndrome
= 44 + XXY = 47 |
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females missing an x chromosome
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turner syndrome (monosomy x)
= 44 + X = 45 |
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males with an extra y chromosome
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speck syndrome
= 44 + XYY = 47 |
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down syndrome
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trisomy 21
= 3 #21 = 2N = 47 |
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females with an extra x
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trisomy x
= 44 + XXX = 47 |
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chances of down syndrome increase with?
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mother's age
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