chromosome variation and sex determination Flashcards
organisms with multiples of the basic chromosome set are referred to as
euploid
euploid
organisms with multiples of the basic chromosome set
what can vary among closely related species
chromosome number- even if the gene number is the same e.g. chin ease muntjac and indian muntjac have a different number of chromosomes, but about the same number of genes
aneuploidy
individuals whose chromosome number differs by one or a small number of chromosomes
individuals whose chromosome number differs by one or a small number of chromosomes
aneuploidy
how do cells end up with too many or too few chromosomes
non-disjunction
non-disjunction
the reason cells end up with too many or too few chromosomes - occurs during meiosis -when chromosomes do not pair with each other properly, meaning one cell will have 1 too many chromosomes and the other 1 too few
when does non-disjunction occur
meiosis
what increases the chance on on disjunction eveents
as women materials age increases e.g. having a child with down syndrome.. trisomy
trisomy
-3 long chromosomes
![](https://s3.amazonaws.com/brainscape-prod/system/cm/203/889/836/a_image_thumb.png?1483009739)
monsomy
-1 long chromosome
![](https://s3.amazonaws.com/brainscape-prod/system/cm/203/889/837/a_image_thumb.png?1483009749)
karyotype
a test to identify and evaluate the size, shape and number of chromosomes in a sample of body cells
euploid detail
typical eukaryotes are haploid or diploid, with one or two complete sets of chromosomes. -Organisms with more or few than the normalnumer are aberrant euploid
polyploids
have nice than two chromosome sets
types of polyploids
triploid, tetraploid, pentaploid and so forth
one setoff chromosomes
monoploid
aneuploidy detail
an aneuploidy can have a chromosome bnymber either greater or smalltimer than the wild type
the aneuploid 2n+1 is
trisomic (three bodies)
the aneuploid with 2n- 1 is
monosomic
the aneuploid 2n-2 is
nullisomic
0
absent e.g. xxy, xyy, xxx, xo
does polyploidy and aneuploidy always result in abnormal development
no e.g. mal bees, wasps and ants are monoploid–> developing from unfertilised eggs