Term
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Definition
Heterozygous for two different traits;
observed at the same time |
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Term
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Definition
Combined expression of two different alleles in heterozygous condition
red+white=pink |
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Term
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Definition
Both inherited alleles are completely expressed
(BLOOD)+ROAN COW |
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Term
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Definition
Genes that exist in populations in more than two allelic forms
(BLOOD) |
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Term
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Definition
One gene affects phenotypic expression of second gene.
RATS one gene shuts of the other |
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Term
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Definition
| Single gene has more than one phenotypic expression |
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Term
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Definition
Interaction of many genes shapes a single phenotype
SKIN |
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Term
| What else can affect phenotypes |
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Definition
temperature
soil condition (pH) |
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Term
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Definition
Genes close together on same chromosome; cannot segregate independently
Greater recombination frequencies = Great distances between genes |
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Term
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Definition
| Map portraying true relative positions of genes based on stained bands |
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Term
| VARIATION INTRODUCED INTO SPECIES |
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Definition
Crossing Over
• During prophase I
Independent assortment of homologues
• During metaphase I
Random joining of gametes
• During fertilization |
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Term
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Definition
| Pair of chromosomes – one from mother; one from father |
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Term
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Definition
| Alleles segregate during meiosis |
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Term
| Law of Independent Assortment |
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Definition
| Homologous chromosomes segregate independently |
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Term
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Definition
| heterozygous for only one trait |
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Term
| What are the different stages? |
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Definition
P generation: Parents
F1 generation: Offspring of parents
F2 generation: Offspring of F1 generation |
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Term
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Definition
| Mating of known genotype with unknown genotype |
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Term
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Definition
1. Need for large Surface-to-volume ratio (S/V)
2. Limited capability of nucleus
• If cell too big, cannot produce enough material to regulate cell activities |
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Term
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Definition
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Term
| Eukaryote – Cell Cycle consist of |
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Definition
Interphase
Mitosis/Meiosis
Cytokinesis |
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Term
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Definition
longest phase takes usually up to 90% of the time. Split into 3 parts
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Term
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Definition
| cell grows more organelles made |
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Term
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Definition
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Term
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Definition
| During this phase cells grow in size, prepare for and synthesize proteins that will be required for cell division in M-phase. In G2 phase, cells also make sure that the DNA was properly replicated in S-phase and repair any DNA |
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Term
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Definition
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Term
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Definition
| Divides nucleus so both daughter cells genetically identical |
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Term
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Definition
Reduction division
Produces daughter cells with ½ genetic information of the parent cell |
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Term
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Definition
| Divides cytoplasm; forms two separate plasma membranes |
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Term
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Definition
Non-dividing state; most human cells are in the G0 phase
Some cells NEVER divide, like nerve and muscle fibers |
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Term
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Definition
Contact (Density-dependent) Inhibition
Cell senescence |
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Term
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Definition
| Limits number of times cell divides |
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Term
| Contact (Density-dependent) Inhibition |
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Definition
• Crowded cells stop dividing
• Some cells may lose contact inhibition & divide uncontrollably – Cancer cell |
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Term
| Checkpoints at G1, G2, and M |
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Definition
• If appropriate signal received, cell completes cell division
• If appropriate signal not received, cell exits cycle and goes to G0
• Controlled by 2 proteins: cyclins and cyclin-dependent kinases
- Kinases - activate or inactivate proteins by phosphorylation |
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Term
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Definition
1. Nucleoli disappear; chromatin condenses into chromosomes joined by a centromere
2. Mitotic spindle begins to assemble
• Controls chromosome movement during mitosis |
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Term
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Definition
1. Nuclear envelope breaks down
2. Microtubules invade nucleus; attach to kinetochores of chromatids |
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Term
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Definition
| protein on centromeres where spindles bind |
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Term
| nonkinetichore fibers do what? |
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Definition
| Nonkinetochore microtubules interact with those from opposite pole and push against eachother splitting cell. |
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Term
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Definition
1. Centrosomes at opposite poles of cell
2. Chromosomes arranged across metaphase plate
Metaphase Plate: Plane lying between two poles of spindle
fastest phase. |
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Term
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Definition
1. Microtubules pull chromosomes apart into two chromatids
•Each chromatid is now a chromosome with centromere and kinetochore
2. Nonkinetochore microtubules lengthen, push poles of cells apart
3. Anaphase ends when each pole has same number chromosomes
Note: Each chromosome now is a single-stranded piece of DNA |
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Term
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Definition
1. Nuclear envelope develops around each pole, forming two nuclei
2. Chromosome within each nuclei disperse into chromatin
3. Nucleoli reappear |
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Term
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Definition
• Usually begins at anaphase; finishes after telophase
(Some cells do not undergo cytokinesis – become multinucleate)
• Divides cytoplasm into two cells |
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Term
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Definition
• Cleavage furrow forms
-Ring of actin and myosin forms and contracts
-Contraction causes cell to pinch into two separate cells |
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Term
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Definition
• Vesicles from Golgi bodies migrate between two newly forming nuclei
• Vesicles fuse to form cell plate
• Cell plate membrane fuses with cell membrane; separates daughter cells
• Cell plate become cell wall |
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Term
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Definition
| • Uses mitosis to produce clone |
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Term
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Definition
• Produces genetically distinct offspring
• Diploid cell(2n)
- Two copies of every chromosome - homologous chromosomes
- One homologue from maternal parent, one from paternal
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Term
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Definition
a haploid (n) gamete
- One copy of every chromosome (½ the original cell) |
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Term
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Definition
• Chromosomes replicate
• Centrosomes replicate |
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Term
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Definition
• Nucleolus disappears
• Chromatin condenses into chromosomes
• Nuclear envelope breaks down
• Spindle Apparatus develops
• Synapsis occurs and forms a tetrad
• Crossing over occurs at chiasmata |
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Term
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Definition
| Criss-crossed chromatids of homologous chromosomes |
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Term
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Definition
| Exchange of genetic material at the chiasmata |
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Term
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Definition
| Protein structure that binds homologs together |
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Term
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Definition
| Pairing of homologous chromosomes Tetrad: Group of four chromatids |
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Term
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Definition
-Homologous pairs align double file at
metaphase plate
- Microtubules extend between poles and
kinetochores
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Term
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Definition
| •Homologues within tetrads uncouple during pull to opposite poles |
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Term
| Telophase I & Cytokinesis |
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Definition
•Chromosomes reach respective poles
•Nuclear membrane develops around chromosomes
•Each pole forms new nucleus with ½ of chromosomes
•Daughter cells are now haploid (half the chromosome #) |
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Term
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Definition
| • Nuclear envelope disappears and spindle develops |
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Term
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Definition
| • Chromosomes align singly on metaphase plate (not in tetrads) |
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Term
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Definition
• Centromeres of sister chromatids separate
• Chromosome becomes two chromatids
• Chromatids (now chromosomes) migrate to respective poles |
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Term
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Definition
• Nuclear envelope reappears at each pole
• Cytokinesis occurs
• Four haploid cells formed (2 from each daughter cell of Telophase I)
• Each cell contains half the chromosomes
• Each chromosome consists of one chromatid |
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Term
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Definition
| Chromosomes not directly involved in determining sex |
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Term
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Definition
Responsible for determining sex
XX – females; XY - males |
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Term
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Definition
| Located on the X chromosome |
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Term
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Definition
| Located on the Y chromosome, very rare, since few genes on Y |
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Term
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Definition
Chromosomes do not properly separate during meiosis
• Both homologous chromosomes migrate to same pole
• Results: ½ gametes missing chromosome
½ gametes have extra chromosome |
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Term
| Down syndrome – Trisomy 21 |
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Definition
| Trisomy 21( 3 chromosome 21's) |
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Term
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Definition
• Nondisjunction of sex chromosome
Sperm are XY or O; Eggs are either XX or O
• Zygote(XO) is female with one X (from normal egg or sperm) |
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Term
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Definition
Nondisjunction of Y XYY
makes you taller |
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Term
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Definition
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Term
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Definition
| •Chromosomal segment deleted |
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Term
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Definition
| •Chromosome segment duplicate |
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Term
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Definition
XXY and male –
Union of XX gamete and normal Y gamete |
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Term
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Definition
segment moved from one chromosome to another
•Reciprocal – nonhomologous chromosomes exchange fragments
•Nonreciprocal – chromosome fragment transferred; does not get one in return |
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Term
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Definition
| • Segment reverses itself within a chromosome |
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Term
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Definition
| Allele expression depends if inherited from mom or dad |
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Term
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Definition
AUTOSOMAL RECESSIVE GENETIC DISEASES
Can’t digest phenylalanine it accumulates & causes mental retardation-
Avoid symptoms by diet low in phenylalanine |
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Term
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Definition
Deletion of portion of chromosome 5
Physical and mental retardation and catlike
Deletion |
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Term
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Definition
Abnormal hemoglobin it substites the “wrong” amino acid
RBC unable to transport O2
autosomal recessive |
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Term
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Definition
Problem breaking down lipids – accumulate in brain cell
Nervous system problems - usually fatal by age four
autosomal recessive |
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Term
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Definition
Expressed in middle age- mild mental illness, loss of motor control
Progresses to total physical and mental incapability
autosomal recessive |
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Term
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Definition
Defective or absent chloride channels creates excessive mucous
autosomal recessive |
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Term
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Definition
Inability to code for clotting factor to form normal blood clots
sex linked |
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Term
| Red-green color blindness |
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Definition
Inability to distinguish red from green
sex linked |
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Term
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Definition
Absences of certain muscle protein.
Results in deterioration of muscle/loss of coordination
sex linked |
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