Answer:
Half of the males are colorblind, dwarf and the other half colorblind, normal height.
Explanation:
The achondroplastic dwarf man with normal vision has a DdXY genotype. He marries a color-blind woman of normal height, so the hergenotype is ddX (c) X (c). All males will be colorblind as they inherit the X (c) chromosome from their mother. Half of them will be of normal height. So half of her boys will be colorblind and of normal height. To see how it works genetically, the cross is:
DdXY x ddX (c) X (c)
Your children have one of the four possible genotypes:
DdXX (c) (female, normal vision, colorblind carrier, dwarf)
DdX (c) Y (male, colorblind, dwarf)
ddXX (c) (woman, normal vision, color blindness carrier, normal height)
ddX (c) Y (male, colorblind, normal height)
Nondisjunction is the failure of a pair of chromosomes to separate (to disjoin) during cell division (meiosis). When this happens ( in anaphase I of meiosis) two out of the four new daughter cells produced from a parent cell will have an extra copy of one chromosome and the other two daughter cells will end up missing that chromosome.
Most of the time when fertilization involves gametes with an abnormal number of chromosomes, the resulting cell does not survive to produce a new individual. However there are some cases where the individuals survive and such, when they are born end up having a syndrome caused by too many or too few chromosomes. An example is Turners syndrome caused by too few chromosomes (monosomy x) , and Down syndrome caused by too many chromosomes (trisomy 21).
Answer:
Nondisjunction is the failure of a pair of chromosomes to separate during meiosis.
Explanation:
Natural disasters can lead to genetic drift by causing changes in population size and composition. They can result in the loss of genetic variation, founder effects, and bottleneck effects.
Natural disasters can contribute to genetic drift by causing significant changes in the population size and composition of a species. These events can lead to a random loss of genetic variation by causing the death of certain individuals or wiping out entire populations. For example, in a wildfire, individuals with certain genetic traits may be more vulnerable to the fire and are therefore less likely to survive and reproduce, leading to a decrease in the frequency of those traits in future generations.
In addition, natural disasters can also result in founder effects and bottleneck effects. A founder effect occurs when a small group of individuals become isolated from the larger population and establish a new population. The genetic diversity of this new population is greatly reduced compared to the original population, leading to genetic drift. Similarly, a bottleneck effect occurs when a large population undergoes a drastic reduction in size, reducing genetic diversity. Both of these effects can be caused by natural disasters, such as earthquakes or hurricanes.
Overall, natural disasters can have a significant impact on genetic drift by influencing the frequency and distribution of genetic traits within a population.
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Answer:
big changes in environmental conditions can sometimes cause large changes to the gene pool of a species
Explanation:
hope this helps!
B. Mammals use a closed, single-loop circulatory system aided by a four-chambered heart.
C. Mammals use an open, double-loop circulatory system aided by a four-chambered heart.
D. Mammals use a closed, single-loop circulatory system aided by a three-chambered heart.