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[Homozygote] | having two identical alleles for a specific gene
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[Homologous chromosomes] | a pair of chromosomes, one from each parent, which carry genes for the same traits, in the same order. in a karyotype, the members of a homologous pair look alike, for example, the pair of chromosome 1 look alike.
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[Heterozygote] | having two different alleles for a specific gene.
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[Heterodisomy] | one of two types of uniparental disomy (the other is isodisomy, defined below); when both copies of a particular chromosome are inherited from the same parent, but the two copies are different (each loci has 2 different alleles). |
[Haploid] | a single set of chromosomes (half of the full set of genetic material). in humans, the haploid number of chromosomes is 23.
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[Gestation] | the carrying of an embryo or fetus during a pregnancy. most pregnancies are single gestations, but multiple gestations can occur (twins or triplets). a 40 week gestational period is considered normal and women are given due dates 40 weeks after they conceived. a baby born after a gestational period of less than 37 weeks is considered to be premature, and pregnancies are rarely allowed to go beyond 42 weeks gestation (the mother will be induced).
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[Germ cell] | a sex cell or reproductive cell; sperm in males and eggs in females
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[Genotype] | the actual genes carried by an individual
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[Genetic counselling] | an educational and supportive process that helps individuals, couples, or families understand genetic information including recurrence risks and reproductive choices that may be available to them.
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[Generalized mosaicism] | if a mistake in cell division occurs very early in development (before differentiation between embryonic and extra-embryonic) that results in some of the cells being trisomic (ie having 47 chromosomes instead of the normal 46), a greater proportion of the cells, and thus most tissues in the body will be affected.
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