Scientists have created mice with two biological fathers by generating eggs from male cells, a development that opens up radical new possibilities for reproduction.
Scientists have created mice with two biologically male parents for the first time - a significant milestone in reproductive biology. JAPAN -- Scientists have created mice with two biologically male parents for the first time - a significant milestone in reproductive biology.
Scientists described their work in a study published Wednesday in the journal Nature. First, they took skin cells from the tails of male mice and transformed them into “induced pluripotent stem cells,” which can develop into many different types of cells or tissues.
Sexual maturity: both male and female mice are sexually mature at 8 weeks and can mate and give birth.
Japanese scientists have created mice with two biological fathers after they generated eggs from male cells for the first time — an advancement which has the potential to radically alter the course of reproductive biology.
Occasionally, two sperm are known to fertilize a single egg; this 'double fertilization' is thought to happen in about 1% of human conceptions. An embryo created this way doesn't usually survive, but a few cases are known to have made it — these children are chimaeras of cells with X and Y chromosomes.
Yes, it is possible for a baby to have two biological fathers through the phenomenon known as “bipaternalism” or “heteropaternal superfecundation”. This occurs when a woman ovulates twice within the same menstrual cycle and has sexual intercourse with two different men during that time.
Loss of Sox9 in XY embryos, or Rspo1 in XX embryos, leads to mice developing physical characteristics that do not match their genetic sex, a phenomenon known as sex reversal.
It is widely recommended to group-house male laboratory mice because they are 'social animals', but male mice do not naturally share territories and aggression can be a serious welfare problem. Even without aggression, not all animals within a group will be in a state of positive welfare.
Mice reproduce sexually. They will mate if left together for two heat cycles, usually ten days. Contrary to some wives tales, mice must mate to reproduce. Female mice have an estrous cycle, or reproductive cycle, that lasts 4 to 6 days long.
But, 80–90% of male mice commit infanticide between 1–4 days after mating. Between 12 and 50 days after mating infanticide is inhibited and most males (80–100%) behave parentally toward young (they build a nest, retrieve and groom the young, and hover over the young to keep them warm).
Baby mice have been made with two mums and no dad, say researchers at the Chinese Academy of Sciences. It took a substantial feat of genetic engineering to break the rules of reproduction. The scientists said the "bimaternal" (two mammas) animals were healthy and went on to have pups of their own.
A mouse can get pregnant immediately after giving birth and can reproduce anywhere from 5 – 10 times per year!
"While we were studying social behaviors in mice, we sometimes noticed that male mice would mount other males, in a way similar to how they would mount females," Karigo says.
Mice have been inbred to reduce genetic variance for over a 100 years, and each generation of inbreeding is expected to lead to a decrease in heterozygosity (Wright 1921; Silver 1995).
Once the males have been neutered and fully recovered from the procedure, they can be reunited once again as long as the mix is successful. Now the neutered males can be introduced into groups of female mice, or live as pairs.
Aggression in male mice often leads to injury and death, making social housing difficult.
If a stock of mice were truly random bred, it would be maintained through matings that were set up randomly among the breeding-age members of the population. Accordingly, matings would sometimes occur between individuals as closely related as siblings.
Instead, normal wild mice use a set of species-specific urinary proteins to avoid inbreeding that has evolved to provide optimized characteristics for effective signaling through their urine scent-marking system.
In a study published in Science Advances on Friday, Japanese scientists suggested that cells of the endangered Amami spiny rat, from Japan, are sexually flexible and capable of adapting to either ovaries or testes.
This is the case with clownfish and also many invertebrates such as some cnidarians (a group that includes hydras and jellyfish), sea sponges, annelids, mollusks, flatworms, starfish and arthropods. Among vertebrates, sex change is widespread in fish and even occurs in some frog species.
For long, many researchers have relied exclusively on male rodents for animal experiments, primarily to avoid the physiological variability linked with the estrous cycle of female rodents.
Male fetal progenitor cells persist in maternal blood for as long as 27 years postpartum. Division of Genetics, Children's Hospital, Boston, MA, USA.
Chimerism occurs when a woman is pregnant with twins and one embryo dies, and the other embryo absorbs the twin's cells. (Scientifically speaking, this type of chimerism is called tetragametic because the baby was derived from four gametes – one egg and one sperm for each embryo.)
Can twins have different fathers? In rare cases, fraternal twins can be born from two different fathers in a phenomenon called heteropaternal superfecundation. Although uncommon, rare cases have been documented where a woman is pregnant by two different men at the same time.