2.13 Mendelian genetics Flashcards
_______ creates genetically identical offspring. what organisms do this?
- asexual reproduction
- bacteria, single celled organisms, plants, worms
Diploid cells have ____ set(s) of chromosomes and haploid cells have _____ set(s)
2,1
what are the benefits of sex?
- mixes 2 genomes
-competitive advantage
zygote
a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.
gamete
mature haploid male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote.
______ are produced from diploid cells through meiosis
haploid germ cells (egg and sperm)
each chromosome consists of 2 ______
sister chromatids
how are mitosis and meiosis 1 metaphase similar?
- Mitosis: homologous chromosomes line up
- Meiosis 1: homologous chromosomes are paired at metaphase plate
crossing over
Crossing over is the exchange of genetic material between non-sister chromatids of homologous chromosomes during meiosis, which results in new allelic combinations in the daughter cells.
______ pull the chromosomes which just crossed over in separate directions
kinetochores
the 2nd meiotic division produces _________
haploid daughter cells
know basic steps of meiosis/mitosis
what 2 things can cause variation?
- independent assortment
- crossing over during meiotic prophase I
meiotic non-disjunction can cause what?
trisomy, monosomy
how did Mendel study inheritance?
by breeding pea plants
In Mendels experiment, what colors were F0, F1, F2 generation?
F0: yellow parent, green parent
F1: all yellow
F2: 75% yellow, 25% green
Discrete/discontinuous traits
controlled by a small number of genes, often only one. These genes generally have two alleles (BB, Bb, bb)
each gamete carries _____ for each character/trait
one single allele
know how to work a simple Yy x Yy punnett square
Mendel’s law of segregation applies to all sexually reproducing organisms. What is this law?
During the formation of gamete, each gene separates from each other so that each gamete carries only one allele for each gene
characteristics of autosomal recessive disorder?
- affect both M/F
- skips generation
ex of autosomal recessive disorder:
albinism
incest makes what more likely to occur?
homozygous recessive diseases
alleles for different traits segregate _____
independently
Chromosomes’ behavior during meiosis underlies Mendels laws of inheritance, How?
gametes assort independently
crossing over (complicates things)
you get variety of gametes
the closer genes are on a chromosome, the less likely what is to happen?
for them to be separated by crossing over
chromosome crossing over can be used to determine what?
the order of genes (what stays together during crossing over will usually be close)
mutations in genes can cause a ______ of function
loss OR gain
recessive allele usually does what?
reduces/eliminates activity of the gene (the dominant gene over-rules usually)
- loss of fxn
overactive mutations usually _____.
dominant (make too much)
what are the types of mutations?
loss of function (point, truncation, deletion)
gain of function
conditional (only at certain temps for ex)
we all may have harmful recessive alleles but why dont we see them?
we usually wont reproduce with someone that has the same recessive allele (except cousins)
_______ can be used to injure the DNA to see what happens
mutagen
example of conditional mutation?
cell stops growth at certain temp. you can breed this cell and see if it shows up again
C. elegens mutation makes what happen?
eat separately and not in clumps like normal
do phenotypes always have to be caused by the same gene?
NO
how can you tell if a mutation is caused by the same gene?
a complementation test
what are SNPs?
every ~1000 nucleotides we have 1 nucleotide different (single nucleotide polymorphism)
SNPs can be landmarks for what?
genetic mapping
disruptions in SNP patterns may indicate what?
location of mutant gene
haplotype
“haploid genotype”
- group of alleles from closely linked loci that are usually inherited as a unit
- set of restriction fragment lengths closely linked to one another and to a gene of interest
-can stay consistent no matter whats surrounding them
haplotype blocks can give clues to what?
evolutionary history
you can trace _______ to reveal the location of a disease carrying gene
the inheritance of SNPS within a haplotyope block
autosomal dominant
heterozygous individual has phenotype
autosomal recessive
heterozygotes don’t have phenotype
sex linked
allele on X chromosome
why might a recessive trait have a survival advantage? EX?
sickle cell anemia makes you malaria resistant
what is the cause of sickle cell anemia?
A–>T change, glu –> val
sickle cell Hb is _____ soluble than normal Hb
less (RBC more fragile too)
there is an association with patients who have sickle cell anemia and ______
DMFT index
complex traits are influenced by _______
multiple genes
some human traits are influenced by ______
environment
