Ch.9 Inheritance Flashcards
This is the idea that the hereditary materials contributed by the male and female parents mix in forming the offspring.
Blending hypothesis
The transmission of traits from one generation to the next.
Hereditary
The scientific study of heredity
Genetics
This was stated that inheritable factors like genes retain their individuality generation after generation. That genes are like playing cards- a deck may be shuffled but the cards always retain their original identities.
Mendels theory.
A heritable feature that varies among individuals
Character
A variant for a character found within a population.
Trait
Varieties for which self-fertilization produced offspring are identical to the parent.
True breeding
The offspring of two different varieties.
Hybrids
Cross fertilization or hybridization
Cross
P-generation
True breeding parents
F1 generation
Hybrid offspring (f is for filial)
F2 generation
When a F2 plants set fertilize or fertilize each other their offspring are F2
Monohybrid cross
Follows one character
Alternative versions of a gene. For each character an organism inherits two of these, one from each parent and it may be identical or different.
Alleles
An organism that has two identical alleles for a gene.
Homozygous
An organism that has two different alleles for a gene.
Heterozygous
Of the two alleles of an inherited differing pair, this is the alleles that determines the organisms appearance.
Written with an uppercase italics letter.
Dominant allele
This has no noticeable effect of the organisms appearance. Written with a lower case italic letter.
Recessive allele
- A sperm or egg carries only one allele for each inherited characteristic because allele pairs separate from each other during the production of gametes.
- When sperm and egg unite at fertilization each contributes its allele restoring the paired condition in the offspring.
- This applies to all sexually reproducing offspring.
Law of segregation
This highlights the four possible combinations of gametes and the resulting four possibly offspring in the F2 generation.
Punnett square
This is an organisms physical traits
Phenotype
This is an organisms genetic makeup.
Genotype
Chromosomes that carry alleles of the same gene.
Homologs
Specific locations of a gene along the chromosome.
Gene locus
Alleles of a gene reside at the same ____ on homologous chromosomes.
Locus
Two homologous chromosomes may bear either ______ alleles at a locus or _____ alleles.
Identical, homozygous
Different, heterozygous
A mating of parental varieties differing in two characters.
Dihybrid cross
Alleles inherited together as they come from the P generation.
Dependent assortment
Genes inherited independently
Independent assortment
The inheritance of one character has no effect on the inheritance of another.
Mendels law of independent assortment
A mating between an individual of unknown genotype and a homozygous recessive individual.
Test cross
The segregation of alleles pairs during gamete formation and the reforming of pairs at fertilization obey the rules of what?
Probability
A probability scale ranges from ____ to _____.
0-1
An event is certain to occur has a probability of ____.
1
An event that is certain not to occur has probability of 0.
0
A rule stating that the probability of a compound event is the product of the separate probabilities of the independent events.
Rule of multiplication.
A rule stating that the probability that an event can occur in two or more alternative ways is the sum of separate probabilities of the different ways.
Rule of addition
What is the probability that an offspring from a genotype AaBbCv will be a recessive homozygous for all 3 genes (aabbcc)?
1/4 x 1/4 x 1/4= 1/64
This describes the traits of parents and children across generations. A family tree with a families history for a trait.
Pedigree
Mendels law and simple logic enable us to deduce the genotypes for nearly every person in the ______.
Pedigree
A trait that is ____ does not mean that it is “normal”- or more common than a recessive trait.
Dominant
Those traits seen most often in nature- not necessarily specified by dominant alleles.
Wild type traits
______ means that a heterozygote (Aa) displays the dominant phenotype.
Dominant
The phenotype is seen only in homozygotes (aa). These traits may be more common in the population.
Recessive
Refers to a trait that is less common in nature.
Mutant trait
Most people who have recessive disorders are born to normal parents who are both ________. They are carriers of the recessive allele for the disorder but are phenotypically normal.
Heterozygotes
Using ______ _____ we can predict the fraction of affected offspring likely to result from a mating between two carriers.
Mendels law
Genetic disorders
- not evenly distributed across all ethnic groups
- such uneven distribution is the result of prolonged geographic isolation of certain populations
Harmless dominant conditions include…
- polydactyly
- webbed fingers
Serious dominant disorders…
- achondroplasia- dwarfism
- Huntington’s disease
This type of genetic testing is performed in uterine between 14&20 weeks pregnant. A needle is I steered through the abdomen and into the amniotic fluid and 10mL is removed.
- cells are karyotyped to detect chromosomal abnormalities.
Amniocentesis
Genetic testing that extracts a tiny sample of chronic villus tissue from placenta.
- tissue obtained using a narrow flexible tube inserted through the vagina and cervix into the uterus.
- speed is an advantage to amniocentesis
Chrionic villus sampling (CVS)
This type of genetic testing measures the mothers blood level of alphafetoprotein (AFP) a protein produced by the fetus.
Blood tests
What are the types of fetal imaging?
Ultrasound and fetoscopy
This is the type of inheritance in which the phenotype of a heterozygote (Aa) and dominant homozygotes (AA and aa) are indistinguishable.
Incomplete Dominance
Most genes can be found in populations in more than two versions is called?
Multiple alleles
What is an example of multiple alleles?
ABO blood group
Describe the ABO blood group.
A phenotype in humans involves three alleles of a single gene with various combinations of 3 alleles.
What four phenotypes can be produced from the ABO blood group?
4
A, B, AB and O
What do the letters in blood type refer to?
Refers to two carbohydrates A&B than may be found on the surface of RBCs
Why is matching blood types important?
Because if a donors blood cells have a carbohydrate that is foreign to the recipient then the recipients immune system produces antibody proteins.
One gene influencing multiple characters is called?
Pleiotropy
The additive effects of two or more genes on a single phenotype character. The opposite of pleiotropy.
Polygenetic inheritance
What are the 4 types of inheritance?
- Incomplete dominance
- Codominance
- Pleiotropy
- Polygenic inheritance
Individual features of any organism arise from a combination of ____ and ____ factors.
Genetic and environmental
This theory holds that genes occupy specific loci in chromosomes and it is the chromosomes that undergo segregation and independent assortment hiring meiosis.
Chromosome theory of inheritance
It is the behavior of chromosomes during meiosis and fertilization ray accounts for _______ patterns.
Inheritance
Genes on the same _____ tend to be inherited together.
Chromosome
The number of ____ in a cell far exceeds the number of chromosomes and there are hundreds of thousands of these on each chromosome.
Gene
Genes located close together on the same chromosome tend to be inherited together. This is called?
Linked genes
Why do linked genes tend to be inherited together and not sort independently?
Because they are located close together on the same chromosome.
During meiosis _______ ______ between homologous chromosomes produces new combinations of alleles in gametes.
Crossing over
Two linked genes can give rise to _____ different gamete genotypes.
Four
The percentage of recombinant offspring among the total
Recombination frequency
This is a diagram of relative gene locations valuable in establishing the relative positions of many genes in many organisms.
Linkage maps
This gene on the Y chromosome plays a crucial role for sex determining region of Y
SRY
SRY triggers ____ development and the absence of this _____ develops.
Testis
Ovaries
A gene located on either sex chromosome. Because the human X chromosome contains many more genes than Y the majority of sex linked genes are on the X chromosome.
Sex linked gene
Human sex linked disorders affect mostly ______.
Makes
A number of human conditions result from sex linked recessive alleles located on the ____ chromosome.
X
The ____ chromosome can be particularly useful for tracing our evolutionary past because this human chromosome passes essentially intact from father to son.
Y
