Genetic Variation Flashcards
What are tandem repeats?
Can be up to several thousand nucleotides and present next to eachother in identical or near identical copies
What are simple sequence repeats?
Can be as short as 2 nucelotide sequences and repeated over and over
What are DNA polymorphisms?
-One of 2 or more alternative forms (alleles) at a chromosomal region (locus)
-Can differ by 1 nucleotide or repeats
-Mostly found in noncoding regions
-Used as DNA markers for analysis
It is extremely __________ any ____________ individuals have the same variable number of tandem repeats (VNTRs)
unlikely, unrelated
_______ variations occur in noncoding regions
silent
What is the cause of sickle cell anemia?
-Genetic variation in beta globin alleles
-SCA is due due being homozygous for the HbS allele
-Individuals can not make functional beta globin proteins
-Cells are sickle shaped and prone to clotting, poor at carrying oxygen, and cause acute pain and fatigue
In microarray, greater _______ means more _______
fluorescence, gene copies
How many haploid sperms cells does a male produce through meiosis?
4 haploid sperm cells from one sex precursor
How many haploid egg cells does a female make from one sex cell precursor?
1 large egg and 3 polar bodies (polar bodies are small and only present to reduce chromosome content and keep it haploid)
What happens in prophase I
-Chromosome condensation
-Synapsis (pairing) of homologous chromosomes facilitated by synaptonemal complex
-Crossing over
What happens in metaphase I
-Homologous chromosome bivalents become randomly arranged relative to eachother at metaphase plate by microtubules
What happens in anaphase I
-Proteins holding homologous pairs together break down
-Pairs are separated to opposite poles
-Sister chromatids do not separate
What happens in telophase I
-Each cell has a haploid set of chromosomes
-Each chromosome is a pair of recombinant sister chromatids
-Followed by cytokinesis and meiosis II
Meiosis is often referred to as __________ _____________ because the cells have the same number of chromosomes as all gametes produced at the end of meiosis II
equational division
_______________ happens when a pair of homologous chromosomes fail to separate in meiosis I or II
Nondisjunction
Mendel bred ___________ parent plants, they would only produce certain traits over many ___________
true breeding, generations
In mendels peas, __________ and ___________ were dominant traits
yellow, smooth
When F1 was allowed to self pollinate, they did not _____________, they bred _________________ ______
breed true, dominant-recessive 3:1
What is mendels law of segregation?
2 alleles of a gene segregate intp different gametes during gamete formation in both parents
Offspring inherits 2 alleles for a gene, dominant allele determines the phenotype
What is Mendels law of independent assortment?
-The alleles of 2 or more different genes get sorted into gametes independently of one another
-Only applies to allele pairs on different chromosomes
_dependent on nonhomologous chromosome alignment during meiosis I
-If genes are located on the same gene, they will not show independent assortment and may be linked if they are close enough together
What is another name for nondisjunction?
Aneuploidy
What is klinefelter syndrome?
XXY, 47
Tall, feminized physique, breast development, less body hair, sterile, small testes
what is trisomy 21
down syndrome, 47, 21+
what is trisomy 13?
patau syndrome, 47, 13+
cleft palate, deaf, malformed organs
what is trisomy 18?
Edwards syndrome, 47, 18+
Small birth weight, low ears, webbed neck, receding chin, malformed organs
What is Turner syndrome?
45, XO
short stature, webbed neck, shield like chest, immature sex organs, sterile
What is Triple X syndrome?
47, XXX
Normal phenotype, tall, fertile, menstrual irregulation, learning disabilities
What is Jacobs syndrome?
XYY, 47
Tall, fertile, normal intelligence
