Chapter 2 & 3 Flashcards
What is classical genetics?
Dealing with the inheritance of traits ie., Mendel.
What is molecular genetics?
The study of DNA, RNA, and gene expressions.
What is evolutionary genetics?
The interaction of gene pools and the environment.
What is a gene?
A unit of hereditary material.
What is a gene locus?
The location of a gene on a chromosome.
What is an allele?
A specific type of gene.
What is a genotype?
A combination of the alleles.
What is a phenotype?
The physical affect of the genotype.
What is a wild type phenotype?
The most prevalent phenotype.
What is a mutant phenotype?
A deviation from the wild type as a result of allelic changes.
What is dominance?
When one of the allele masks the phenotype of another.
What is recessive?
When one alleles phenotype is not determined until the allele is homozygous.
What is a loss of function mutation?
A significant decrease or complete loss of gene. product
What is a gain of function mutation?
A gene product acquires a new function or has an increased expression above wild type.
What is incomplete dominance?
When there is a heterozygote genotype that leads to a blending of the phenotype.
What is codominance?
When both alleles of a heterozygote genotype are expressed.
What is haplosufficiency?
When one of the alleles provide enough gene product to be wild type so, the mutant is recessive.
What is haploinsufficiency?
When one of the alleles is not enough gene product to be wild type so the mutant is dominant.
What is a monohybrid cross?
A cross between two organisms having to do with 1 trait.
What is Mendel’s First Law or Law of Equal Segregation?
Half of the gametes carry one member of the gene pair and the other gamete contains the other member there is an equal proability of inheriting either one.
What is a test cross?
A method of determining the genotype of either homozygous dominant or heterozygous using a recessive pure breed.
What does (n) refer to?
Not the individual chromosomes but the number of sets of the chromosomes.
What are telomeres?
These are the ends of the chromosomes that consist of repeated DNA regions that are shaved off after every cell division so, it can determine the the age of the cell and organism.
What are the P and Q Arm?
These are the short and long sides of the chromosomes respectively.
What is the centromere?
This is the center of the chromosome that consists of compacted chromatin through special types of kinetochore and histone proteins.
What is metacentric?
This is when the centromeres are relatively in the middle.
What is acrocentric?
This is when the centromere is closer to one side then the other.
What is telocentric?
This is when the centromere is completely at one end compared to another.
What are chromosomes?
These are chromosomes that consist of DNA and are condensed by proteins called the histones and compact the DNA into chromatin.
What is a chromatid?
These are individual strands that make up the chromosomes.
What are sister and non-sister chromatids?
Sister chromatids have the exact same alleles while non-sister chromtids do not have the exact same alleles.
What are the main phases of cell division?
1.)G1
2.)S
3.)G2
4.)M
What is the Synaphtonemal Complex?
It is the unit that holds the homologous chromosomes together.
What are the 2 types of cell division?
1.) Somatic cell division
2.) Sexual cell division
What is sex linkage?
This is when the sex chromosomes have genes attached that vary depending on the sex of the organism.
What is homogametic?
A matching pair of sex chromosomes.
What is heterogametic?
A non-matching pair of sex chromosomes.
What is a propositus?
The first member of the family who comes to the attention of the geneticist and ususally has the disease.
What is the autosomal recessive pedigree?
This is when the parents are not affected but the offspring are, if both parents are affected then all children will be, and both males and female have an equal chance of having the trait.
What is the autosomal dominant pedigree?
No generation is skipped, either male or female can trasmit the mutant allele to their son or daughter, and 2 affected parents can produce a non affected child.
What is a rare disease?
When the carriers are not common so, whenever an individual marries into the family it is homozygous for the unaffected allele.
What is polymorphism?
When the carriers are common in population and there are multiple phenotypes present at the same time.
What is X-linked recessive?
When more males than females are affected, if the father is affected but none of his offspring are affected, and all male offspring from an affected female will be affected.
What is X-linked dominant?
All daughters of an affected male will be affected, and no sons will be affected unless the mother is affected.
What is a dihybrid cross?
A cross relating 2 traits.
What is the Law of Independent Assortment or Mendel’s Second Law?
Different gene pairs that are unlinked assort independently and randomly during gamete formation.
What is recombination?
When a cell has DNA or genetic material that generates new gene combinations that were not found in the diploid.
How does the lettering differ for a gamete?
Since it is a haploid only use one of the letters.
What are the 3 methods of determining ratios?
1.) Punnett square
2.) Branch diagrams
3.) Product rule
What is the product rule?
Multiplying the probability of independent events.
What is the sum rule?
When the first or second event will occur and they are mutually exclusive.
What does a gene do?
It is the DNA sequence that is involved in making RNA and then proteins.
What is the genome?
This is the entire DNA sequence (ACGT) of the organism.
Where are genes found?
Genes are found on chromosomes and are parts of the genome that encode the RNA and the protein.
Which is the daughter strand?
This is the replicated or new strand of DNA.
What are chromosomes?
These are condensed DNA strands that include both the DNA as well as its associated proteins.
What is chromatin?
This is a specific region of DNA and its associated proteins.
What are centromeres?
These are the centers of a pair of sister chromatids which are then connected to the spindle fibers to pull them apart during anaphase of mitosis and meiosis.
What is a haploid?
This is the n set of chromosomes and the number of genes.
What is a diploid?
This is the double set of chromosomes and the number of genes 2n.
What is homologous chromosomes?
These are the replicated chromosomes which are the same due to the replication process.
What is the cell cycle?
This is the process in which the cell grows, replicated DNA, and forms daughter cells.
What is the G1 and G2 phase?
These are the gap phase where the proteins and necessary material are made for cell division.
What is the S phase?
The phase where DNA replicates.
What are the 3 checkpoints?
1.) DNA damage a the G1/S phase.
2.) DNA replication at the G2/M checkpoint.
3.) Spindle connection at the prometaphase/metaphase point.
What are homologous chromosomes?
These are chromosome pairs that have the same order and number of genes however the alleles could be different.
What are the stages of mitosis?
1.) Prophase
2.) Prometaphase
3.) Metaphase
4.) Anaphase
5.) Telophase
What are the stages of meiosis I?
1.) Prophase I
2.) Prometaphase I
3.) Metaphase I
4.) Anaphase I
5.) Telophase I
What are the stages of meiosis II?
1.) Prophase II
2.) Prometaphase II
3.) Metaphase II
4.) Anaphase II
5.) Telophase II
What is recombination?
During prophase I the process of crossing over occurs where the genes of the non-sister chromatids are exchanged and this exchange must be precise otherwise there will be a loss or gain for the other chromosome.
Which meiosis determines the ploidy?
Meiosis I determines the ploidy as it is the reductional division.
What stages of meiosis show the Law of Equal Segregation?
Anaphase I and II
What stages of meiosis show the Law of Independent Assortment?
Metaphase I
What is the difference between the Law of Independent Assortment and the Law of Equal Segregation?
The Law of Independent Assortment focuses on the alleles and how these chromosomes are assorted independent of each other during gamete formation. The Law of Equal Segregation focuses on the nonhomologous chromosomes and its distribution during gamete formation.
What is a chromatid?
An unreplicated chromosome.
What is a reciprocal cross?
The reverse of the testcross in terms of gender.
What are pure lines?
These are organisms with the homozygous recessive genotype.
How do crosses occur?
Among flowers the pollen from one anther is taken to the stigmata of another flower. However, a self cross occurs when the pollen from one anther is taken to its own stigmata.
What is the phase that the Law of Equal Segregation matters?
Anaphase of mitosis or Anaphase I of meiosis
What is a null allele?
It is an allele where the proteins produced by them lack complete functioning.
What is a leaky mutation?
This is when a mutant lacks function however the wild type phenotype starts to leak through.
What is a silent mutation?
This is when the mutation does not have an impact on the phenotype.
What is X-linkage?
This is when the mutant alleles are found on the differential region of the X-chromosome.
What is Y-linkage?
This is when the mutant alleles are found on the differential region of the Y-chromosome.
What is the Chromosome Theory of Inheritance?
This is when the genes on a chromosome control the inheritance patterns of the trait.
Why do males have a higher chance of getting an X-linked recessive disease?
Males have a higher chance because they only get 1 X chromosome therefore if the mom has the trait or is a carrier it just takes the 1 for the trait to occur.
Why do females have a higher chance of getting an X-linked dominant disease?
Females are at a high risk because they have 2 X chromosomes therefore they have 2 chances to get a dominant allele which is haplosufficient.
Why do we observe the number of progeny to determine the confidence?
When we increase the number of progeny the chance of failure decreases therefore we become more confident in the probability when there is a specific progeny number (n) being used.
How do you find the total number of genotypes?
Genotype Possibilites^(# of Gene Pairs)
What 2 elements add to the variation of gametes?
1.) Independent assortment
2.) Crossing over
