Pathak- Inheritance Flashcards
(59 cards)
0
Q
Inheritance
A
The genetic transmission of characteristics from parent to offspring
1
Q
Genes
A
Segments of DNA that carry instructions for synthesizing proteins that determine how an organism develops, looks, and functions
2
Q
Gregor Mendel
A
- monk who lay the foundations for modern genetics
- experimented with the edible pea
3
Q
Locus
A
- Gene’s specific physical location on a chromosome
- nucleotide sequence at a given gene locus is always similar on homologous pairs but not always identical
4
Q
Homozygous
A
An organism whose homologous chromosomes both have the SAME allele at a given gene locus
5
Q
Heterozygous
A
- An organism whose homologous chromosomes both have the DIFFERENT allele at a given gene locus
- also known as a HYBRID
6
Q
Gametes of Homozygous
A
All contain the same allele
7
Q
Gametes of Heterozygous
A
- two kinds
- half with one allele, half with the other
8
Q
Allele
A
Alternate forms of a gene
9
Q
Self fertilization
A
- flower supplies it’s own pollen
- egg cells are fertilized by sperm from the pollen of the same flower
10
Q
True Breeding
A
- plants in which all the offspring produced through self fertilization are homozygous
- identical to the parent plant
11
Q
Cross fertilization
A
- a process in which breeders remove the stamen, preventing self fertilization
- true breeding plants are mated
- dust carpels with pollen
12
Q
Law of Segregation
A
- Each gamete receives only one of each parent’s pair of genes for each trait
- one allele from each parent
13
Q
Genotype
A
- the actual combination of alleles carried by an organism
- PP / Pp
14
Q
Phenotype
A
- Organism’s trait
- any observable feature
- outward appearance, digestive enzymes, blood type
15
Q
Punnett Square
A
A way to predict the genotype and phenotype of offsprings
16
Q
Test Cross
A
Used to test whether the unknown genotype is homozygous or heterozygous by breeding it with a homozygous (pure) recessive
17
Q
Law of Independent Assortment
A
- The alleles for one trait may be distributed to the gametes independently of the alleles for other traits
- happens if the gene loci are on different chromosomes
18
Q
Linkage
A
- inheritance of certain genes as a group because they are on the same chromosome
- tend to be inherited together and do not assort independently
19
Q
Linked Genes
A
Genes on the same chromosome
20
Q
Crossing over
A
- may separate linked genes
- location: chiasmata (where no sister chromatids of homologous chromosomes intertwine during PROPHASE 1)
- segments of homologous pairs are exchanged
- forms new gene combinations on both homologous pairs
21
Q
Genetic recombination
A
The generation of new combinations of alleles by the exchange of DNA between homologous chromosomes during crossing over
22
Q
Sex chromosome
A
- one of the pair of chromosomes that differ between sexes and normally determine the sex of an individual
- always one pair
- females: XX
- males: XY
23
Q
Autosomes
A
Chromosomes that occur in pairs of identical appearance in both males and females
24
Sex- Linked (X- Linked)
Genes that are found only on the X or only on the Y chromosomes
25
X Chromosome
- contain genes for color vision, blood clotting, and certain structural proteins in muscles that have no counterpart on the Y chromosome
- males must fully express all alleles they have on their X chromosome (dominant or not)
26
Incomplete Dominance
- blending
- one allele does not completely dominate over the other
- blending of phenotype is NOT the result of any change in allele
- occurs when both copies of a functional allele are necessary in order to produce enough protein to give rise to the dominant phenotype
27
Multiple allele
- Multiple alleles for every gene
| - ex. Blood type
28
Codominance
- Both phenotypes are expressed
| - ex. AB blood type (both enzymes& A and B glycoproteins are present)
29
Polygenic Inheritance
- a form of inheritance in which the interaction of two or more functionally similar genes contribute to a single phenotype
- ex. Eye color
30
Eye Color
- depends on the amount of pigment in the outer layer of the iris
- blue: little or no pigment
- green/ brown/ black: more melanin
- at least two (or more) genes direct the synthesis of melanin in the front of the iris
31
Pleiotropy
- single genes commonly have multiple phenotypic effects
| - ex. SRY gene
32
Pedigrees
Diagrams that show the genetic relationships among a set of individuals
33
Unattached Earlobe
Dominant
34
Color blindness
- sex linked
| - due to recessive alleles of X chromosome gene
35
Albinism
- Caused if both homologous chromosomes carry a mutation that interferes with melanin production
- recessive
36
Carriers
Phenotypically normal but can pass on heir defective recessive allele to their offspring
37
Sickle Cell Anemia
A recessive disease in which defective hemoglobin is produced
38
Huntington's Disease
- caused by dominant allele
- causes a slow, progressive deterioration of parts of the brain
- symptoms typically do not appear until 30 to 50 yrs of age
- people pass on the allele before they start to suffer the symptoms
39
Sex Linked Inheritance
All the alleles on the X chromosome that have no Y counterpart are expressed
40
Recessive Sex Linked Disorders
- unique pattern
- more frequent in make
- typically skip generations
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Hemophilia
- caused by recessive allele on the X chromosome
| - deficiency of one of the substances important in blood clotting
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Nondisjunction
Errors in meiosis that can affect the distribution of sex chromosomes and autosomes
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Nondisjunction in Males
Sperm are O, XX, YY, or XY
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Women
0 or XX eggs
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Turner Syndrome (XO)
- failure to menstruate/ develop normal secondary sexual characteristics
- sterile
- short
- nuclei lack Barr bodies
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Trisomy X (XXX)
- fertile
- higher incidence of below normal intelligence
- almost always hear normal XX and XY children
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Klinefelter Syndrome (XXY)
- mixed secondary characteristics
- partial breast development, small testes
- sterile
- increased incidence of mental deficiency
48
XYY Males
- below average intelligence
- violent
- above average height
49
YO
Dies as embryo
50
Trisomy 21 (Down's Syndrome)
- extra copy of the 21st chromosome
- weak muscle tone
- small mouth held partially open
- low resistance to infectious disease, heart malformations; mental retardation
- increase parent's age (especially mom) --> increase Nondisjunction
51
Codominance
Shows both (white with red spots)
52
Phenylketonuria (PKU)
- autosomal recessive
| - inability to break down amino acid phenylalanine
53
Cystic fibrosis
- autosomal recessive
| - build up of extra cellular fluid in lungs, digestive tract, etc.
54
Tay- Sachs Disease
- autosomal recessive
| - caused by lack of enzyme needed to break down lipids for normal brain function
55
Duchene Muscular Dystrophy
- sex linked recessive
| - progressive weakening of muscle control
56
NOT Y- linked
If female has it
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NOT X Recessive
If daughter has it, but father does not
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IS Autosomal Recessive
If neither parent has, but child does
